chore: pin release.linux.yaml to arm64-only for sysroot bootstrap test

x64 already builds cleanly — the failing leg is arm64 cross-compile from
an x64 host. Pin the config to arm64 to exercise the new
install-sysroot.py path in configure without burning time on x64.
Flip back to [x64, arm64] once arm64 is green.

.gitattributes

@@ -9,4 +9,6 @@ packages/browseros/chromium_patches/**/*.py linguist-generated
 scripts/*.py linguist-generated
 # Mark build directories as generated
 build/* linguist-generated
+# Mark eval/test framework as vendored so it's excluded from language stats
+packages/browseros-agent/apps/eval/** linguist-vendored
 docs/videos/** filter=lfs diff=lfs merge=lfs -text

.github/workflows/release-server.yml

@@ -0,0 +1,147 @@
+name: Release BrowserOS Server
+
+on:
+  workflow_dispatch:
+    inputs:
+      version:
+        description: "Release version (e.g. 0.0.80)"
+        required: true
+        type: string
+
+concurrency:
+  group: release-server
+  cancel-in-progress: false
+
+jobs:
+  release:
+    if: github.ref == 'refs/heads/main'
+    runs-on: ubuntu-latest
+    environment: release-core
+    permissions:
+      contents: write
+    defaults:
+      run:
+        working-directory: packages/browseros-agent
+
+    steps:
+      - uses: actions/checkout@v6
+        with:
+          fetch-depth: 0
+
+      - uses: oven-sh/setup-bun@v2
+        with:
+          bun-version: "1.3.6"
+
+      - name: Install dependencies
+        run: bun ci
+
+      - name: Prepare production env file
+        run: cp apps/server/.env.production.example apps/server/.env.production
+
+      - name: Validate version
+        id: version
+        env:
+          REQUESTED_VERSION: ${{ inputs.version }}
+        run: |
+          PACKAGE_VERSION=$(node -p "require('./apps/server/package.json').version")
+          echo "package_version=$PACKAGE_VERSION" >> "$GITHUB_OUTPUT"
+          echo "release_sha=$(git rev-parse HEAD)" >> "$GITHUB_OUTPUT"
+
+          if [ "$PACKAGE_VERSION" != "$REQUESTED_VERSION" ]; then
+            echo "Requested version $REQUESTED_VERSION does not match apps/server/package.json ($PACKAGE_VERSION)"
+            exit 1
+          fi
+
+      - name: Build release artifacts
+        run: bun run build:server:ci
+
+      - name: Verify release artifacts
+        run: |
+          mapfile -t ZIP_FILES < <(find dist/prod/server -maxdepth 1 -type f -name 'browseros-server-resources-*.zip' | sort)
+
+          if [ "${#ZIP_FILES[@]}" -eq 0 ]; then
+            echo "No server release zip files were produced"
+            exit 1
+          fi
+
+          printf 'Found release artifacts:\n%s\n' "${ZIP_FILES[@]}"
+
+      - name: Generate release notes
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          PACKAGE_VERSION: ${{ steps.version.outputs.package_version }}
+        run: |
+          SERVER_APP_PATH="packages/browseros-agent/apps/server"
+          SERVER_BUILD_DIR="packages/browseros-agent/scripts/build/server"
+          SERVER_BUILD_ENTRY="packages/browseros-agent/scripts/build/server.ts"
+          SERVER_RESOURCE_MANIFEST="packages/browseros-agent/scripts/build/config/server-prod-resources.json"
+          SERVER_WORKSPACE_PKG="packages/browseros-agent/package.json"
+          CURRENT_TAG="browseros-server-v$PACKAGE_VERSION"
+          PREV_TAG=$(git tag -l "browseros-server-v*" --sort=-v:refname | grep -v "^${CURRENT_TAG}$" | head -n 1)
+
+          if [ -z "$PREV_TAG" ]; then
+            echo "Initial release of browseros-server." > /tmp/release-notes.md
+          else
+            COMMITS=$(git log "$PREV_TAG"..HEAD --pretty=format:"%H" -- \
+              "$SERVER_APP_PATH" \
+              "$SERVER_BUILD_DIR" \
+              "$SERVER_BUILD_ENTRY" \
+              "$SERVER_RESOURCE_MANIFEST" \
+              "$SERVER_WORKSPACE_PKG")
+
+            if [ -z "$COMMITS" ]; then
+              echo "No notable changes." > /tmp/release-notes.md
+            else
+              echo "## What's Changed" > /tmp/release-notes.md
+              echo "" >> /tmp/release-notes.md
+
+              while IFS= read -r SHA; do
+                SUBJECT=$(git log -1 --pretty=format:"%s" "$SHA")
+                PR_NUM=$(gh api "/repos/${{ github.repository }}/commits/${SHA}/pulls" --jq '.[0].number // empty' 2>/dev/null)
+
+                if [ -n "$PR_NUM" ] && ! echo "$SUBJECT" | grep -qF "(#${PR_NUM})"; then
+                  echo "- ${SUBJECT} (#${PR_NUM})" >> /tmp/release-notes.md
+                else
+                  echo "- ${SUBJECT}" >> /tmp/release-notes.md
+                fi
+              done <<< "$COMMITS"
+            fi
+          fi
+        working-directory: ${{ github.workspace }}
+
+      - name: Create GitHub release
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          PACKAGE_VERSION: ${{ steps.version.outputs.package_version }}
+          RELEASE_SHA: ${{ steps.version.outputs.release_sha }}
+        run: |
+          TAG="browseros-server-v$PACKAGE_VERSION"
+          TITLE="BrowserOS Server - v$PACKAGE_VERSION"
+          mapfile -t ZIP_FILES < <(find packages/browseros-agent/dist/prod/server -maxdepth 1 -type f -name 'browseros-server-resources-*.zip' | sort)
+
+          git config user.name "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
+
+          if git rev-parse "$TAG" >/dev/null 2>&1; then
+            echo "Tag $TAG already exists, skipping tag creation"
+          else
+            git tag -a "$TAG" -m "browseros-server v$PACKAGE_VERSION" "$RELEASE_SHA"
+          fi
+
+          if git ls-remote --tags origin "$TAG" | grep -q "$TAG"; then
+            echo "Tag $TAG already on remote, skipping push"
+          else
+            git push origin "$TAG"
+          fi
+
+          if gh release view "$TAG" >/dev/null 2>&1; then
+            echo "Release $TAG already exists, updating"
+            gh release edit "$TAG" --title "$TITLE" --notes-file /tmp/release-notes.md
+            gh release upload "$TAG" "${ZIP_FILES[@]}" --clobber
+          else
+            gh release create "$TAG" \
+              --title "$TITLE" \
+              --notes-file /tmp/release-notes.md \
+              "${ZIP_FILES[@]}"
+          fi
+        working-directory: ${{ github.workspace }}

README.md

@@ -192,7 +192,7 @@ We'd love your help making BrowserOS better! See our [Contributing Guide](CONTRI
 
 BrowserOS is open source under the [AGPL-3.0 license](LICENSE).
 
-Copyright © 2025 Felafax, Inc.
+Copyright © 2026 Felafax, Inc.
 
 ## Stargazers
 

packages/browseros-agent/apps/server/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@browseros/server",
-  "version": "0.0.80",
+  "version": "0.0.81",
   "description": "BrowserOS server",
   "type": "module",
   "main": "./src/index.ts",

packages/browseros-agent/apps/server/tests/build.test.ts

@@ -8,11 +8,16 @@
 
 import { afterAll, describe, it } from 'bun:test'
 import assert from 'node:assert'
-import { mkdtempSync, rmSync, writeFileSync } from 'node:fs'
+import {
+  existsSync,
+  mkdtempSync,
+  readFileSync,
+  rmSync,
+  writeFileSync,
+} from 'node:fs'
 import { tmpdir } from 'node:os'
 import { join, resolve } from 'node:path'
 
-// Derive the build target from the current platform so the test is portable
 function getNativeTarget(): { id: string; ext: string } {
   const os =
     process.platform === 'darwin'
@@ -24,12 +29,30 @@ function getNativeTarget(): { id: string; ext: string } {
   return { id: `${os}-${cpu}`, ext: process.platform === 'win32' ? '.exe' : '' }
 }
 
-// Stub values so the build config validation passes without real secrets
-const BUILD_ENV_STUBS: Record<string, string> = {
+const REQUIRED_INLINE_ENV_KEYS = [
+  'BROWSEROS_CONFIG_URL',
+  'CODEGEN_SERVICE_URL',
+  'POSTHOG_API_KEY',
+  'SENTRY_DSN',
+] as const
+
+const R2_ENV_KEYS = [
+  'R2_ACCOUNT_ID',
+  'R2_ACCESS_KEY_ID',
+  'R2_SECRET_ACCESS_KEY',
+  'R2_BUCKET',
+] as const
+
+const PROD_SECRET_KEYS = [...REQUIRED_INLINE_ENV_KEYS, ...R2_ENV_KEYS]
+
+const INLINE_ENV_STUBS: Record<string, string> = {
   BROWSEROS_CONFIG_URL: 'https://stub.test/config',
   CODEGEN_SERVICE_URL: 'https://stub.test/codegen',
   POSTHOG_API_KEY: 'phc_test_stub',
   SENTRY_DSN: 'https://stub@sentry.test/0',
+}
+
+const R2_ENV_STUBS: Record<string, string> = {
   R2_ACCOUNT_ID: 'test',
   R2_ACCESS_KEY_ID: 'test',
   R2_SECRET_ACCESS_KEY: 'test',
@@ -39,23 +62,58 @@ const BUILD_ENV_STUBS: Record<string, string> = {
 describe('server build', () => {
   const rootDir = resolve(import.meta.dir, '../../..')
   const serverPkgPath = resolve(rootDir, 'apps/server/package.json')
+  const prodEnvPath = resolve(rootDir, 'apps/server/.env.production')
+  const prodEnvTemplatePath = resolve(
+    rootDir,
+    'apps/server/.env.production.example',
+  )
+  const originalProdEnv = existsSync(prodEnvPath)
+    ? readFileSync(prodEnvPath, 'utf-8')
+    : null
+  const prodEnvTemplate = readFileSync(prodEnvTemplatePath, 'utf-8')
   const buildScript = resolve(rootDir, 'scripts/build/server.ts')
   const target = getNativeTarget()
   const binaryPath = resolve(
     rootDir,
     `dist/prod/server/.tmp/binaries/browseros-server-${target.id}${target.ext}`,
   )
-
-  // Empty manifest so the build skips R2 resource downloads
+  const zipPath = resolve(
+    rootDir,
+    `dist/prod/server/browseros-server-resources-${target.id}.zip`,
+  )
   const tempDir = mkdtempSync(join(tmpdir(), 'browseros-build-test-'))
   const emptyManifestPath = join(tempDir, 'empty-manifest.json')
   writeFileSync(emptyManifestPath, JSON.stringify({ resources: [] }))
 
+  function buildEnv(
+    extraEnv: Record<string, string>,
+    omitKeys: readonly string[] = [],
+  ): NodeJS.ProcessEnv {
+    const env: NodeJS.ProcessEnv = {
+      ...process.env,
+      ...extraEnv,
+    }
+    for (const key of omitKeys) {
+      delete env[key]
+    }
+    return env
+  }
+
+  function resetProdEnvToTemplate(): void {
+    writeFileSync(prodEnvPath, prodEnvTemplate)
+  }
+
   afterAll(() => {
     rmSync(tempDir, { recursive: true, force: true })
+    if (originalProdEnv === null) {
+      rmSync(prodEnvPath, { force: true })
+      return
+    }
+    writeFileSync(prodEnvPath, originalProdEnv)
   })
 
   it('compiles and --version outputs correct version', async () => {
+    resetProdEnvToTemplate()
     const pkg = await Bun.file(serverPkgPath).json()
     const expectedVersion: string = pkg.version
 
@@ -71,7 +129,7 @@ describe('server build', () => {
         cwd: rootDir,
         stdout: 'pipe',
         stderr: 'pipe',
-        env: { ...process.env, ...BUILD_ENV_STUBS },
+        env: buildEnv({ ...INLINE_ENV_STUBS, ...R2_ENV_STUBS }),
       },
     )
     const buildExit = await build.exited
@@ -97,4 +155,26 @@ describe('server build', () => {
     )
     assert.strictEqual(versionOutput.trim(), expectedVersion)
   }, 300_000)
+
+  it('archives CI builds without R2 config or production env secrets', async () => {
+    resetProdEnvToTemplate()
+    rmSync(zipPath, { force: true })
+
+    const build = Bun.spawn(
+      ['bun', buildScript, `--target=${target.id}`, '--ci'],
+      {
+        cwd: rootDir,
+        stdout: 'pipe',
+        stderr: 'pipe',
+        env: buildEnv({}, PROD_SECRET_KEYS),
+      },
+    )
+    const buildExit = await build.exited
+    if (buildExit !== 0) {
+      const stderr = await new Response(build.stderr).text()
+      assert.fail(`CI build failed (exit ${buildExit}):\n${stderr}`)
+    }
+
+    assert.ok(existsSync(zipPath), `Expected archive at ${zipPath}`)
+  }, 300_000)
 })

packages/browseros-agent/bun.lock

@@ -152,7 +152,7 @@
     },
     "apps/server": {
       "name": "@browseros/server",
-      "version": "0.0.80",
+      "version": "0.0.81",
       "bin": {
         "browseros-server": "./src/index.ts",
       },

packages/browseros-agent/package.json

@@ -19,7 +19,7 @@
     "start:agent": "bun run --filter @browseros/agent dev",
     "build": "bun run build:server && bun run build:agent",
     "build:server": "FORCE_COLOR=1 bun scripts/build/server.ts --target=all",
-    "build:server:ci": "FORCE_COLOR=1 bun scripts/build/server.ts --target=all --compile-only",
+    "build:server:ci": "FORCE_COLOR=1 bun scripts/build/server.ts --target=all --ci",
     "build:server:test": "FORCE_COLOR=1 bun scripts/build/server.ts --target=darwin-arm64 --no-upload",
     "upload:cli-installers": "bun scripts/build/cli.ts",
     "start:server:test": "bun run build:server:test && set -a && . apps/server/.env.development && set +a && dist/prod/server/.tmp/binaries/browseros-server-darwin-arm64",

packages/browseros-agent/scripts/build/server/archive.ts

@@ -37,29 +37,39 @@ export async function archiveAndUploadArtifacts(
   r2: R2Config,
   upload: boolean,
 ): Promise<UploadResult[]> {
-  const results: UploadResult[] = []
+  const results = await archiveArtifacts(artifacts)
+  if (!upload) {
+    return results
+  }
 
-  for (const artifact of artifacts) {
-    const zipPath = zipPathForArtifact(artifact)
-    await zipArtifactRoot(artifact.rootDir, zipPath)
-
-    if (!upload) {
-      results.push({ targetId: artifact.target.id, zipPath })
-      continue
-    }
-
-    const fileName = basename(zipPath)
+  const uploadedResults: UploadResult[] = []
+  for (const result of results) {
+    const fileName = basename(result.zipPath)
     const latestR2Key = joinObjectKey(r2.uploadPrefix, 'latest', fileName)
     const versionR2Key = joinObjectKey(r2.uploadPrefix, version, fileName)
-    await uploadFileToObject(client, r2, latestR2Key, zipPath)
-    await uploadFileToObject(client, r2, versionR2Key, zipPath)
-    results.push({
-      targetId: artifact.target.id,
-      zipPath,
+    await uploadFileToObject(client, r2, latestR2Key, result.zipPath)
+    await uploadFileToObject(client, r2, versionR2Key, result.zipPath)
+    uploadedResults.push({
+      targetId: result.targetId,
+      zipPath: result.zipPath,
       latestR2Key,
       versionR2Key,
     })
   }
 
+  return uploadedResults
+}
+
+export async function archiveArtifacts(
+  artifacts: StagedArtifact[],
+): Promise<UploadResult[]> {
+  const results: UploadResult[] = []
+
+  for (const artifact of artifacts) {
+    const zipPath = zipPathForArtifact(artifact)
+    await zipArtifactRoot(artifact.rootDir, zipPath)
+    results.push({ targetId: artifact.target.id, zipPath })
+  }
+
   return results
 }

packages/browseros-agent/scripts/build/server/cli.ts

@@ -22,23 +22,26 @@ export function parseBuildArgs(argv: string[]): BuildArgs {
     .option('--upload', 'Upload artifact zips to R2')
     .option('--no-upload', 'Skip zip upload to R2')
     .option(
-      '--compile-only',
-      'Compile binaries only (skip R2 staging and upload)',
+      '--ci',
+      'Build local release zip artifacts for CI without R2 and without requiring production env secrets',
     )
   program.parse(argv, { from: 'user' })
   const options = program.opts<{
     target: string
     manifest: string
     upload: boolean
-    compileOnly: boolean
+    ci: boolean
   }>()
 
-  const compileOnly = options.compileOnly ?? false
+  const ci = options.ci ?? false
+  if (ci && options.upload) {
+    throw new Error('--ci cannot be combined with --upload')
+  }
 
   return {
     targets: resolveTargets(options.target),
     manifestPath: options.manifest,
-    upload: compileOnly ? false : (options.upload ?? true),
-    compileOnly,
+    upload: ci ? false : (options.upload ?? true),
+    ci,
   }
 }

packages/browseros-agent/scripts/build/server/compile.ts

@@ -1,6 +1,7 @@
 import { mkdirSync, rmSync } from 'node:fs'
 import { join } from 'node:path'
 
+import { log } from '../log'
 import { wasmBinaryPlugin } from '../plugins/wasm-binary'
 import { runCommand } from './command'
 import type { BuildTarget, CompiledServerBinary } from './types'
@@ -52,6 +53,7 @@ async function bundleServer(
 async function compileTarget(
   target: BuildTarget,
   env: NodeJS.ProcessEnv,
+  ci: boolean,
 ): Promise<string> {
   const binaryPath = compiledBinaryPath(target)
   const args = [
@@ -66,11 +68,15 @@ async function compileTarget(
   await runCommand('bun', args, env)
 
   if (target.os === 'windows') {
-    await runCommand(
-      'bun',
-      ['scripts/patch-windows-exe.ts', binaryPath],
-      process.env,
-    )
+    if (ci) {
+      log.warn('Skipping Windows exe metadata patching in CI mode')
+    } else {
+      await runCommand(
+        'bun',
+        ['scripts/patch-windows-exe.ts', binaryPath],
+        process.env,
+      )
+    }
   }
 
   return binaryPath
@@ -81,14 +87,16 @@ export async function compileServerBinaries(
   envVars: Record<string, string>,
   processEnv: NodeJS.ProcessEnv,
   version: string,
+  options?: { ci?: boolean },
 ): Promise<CompiledServerBinary[]> {
+  const ci = options?.ci ?? false
   rmSync(TMP_ROOT, { recursive: true, force: true })
   mkdirSync(BINARIES_DIR, { recursive: true })
   await bundleServer(envVars, version)
 
   const compiled: CompiledServerBinary[] = []
   for (const target of targets) {
-    const binaryPath = await compileTarget(target, processEnv)
+    const binaryPath = await compileTarget(target, processEnv, ci)
     compiled.push({ target, binaryPath })
   }
 

packages/browseros-agent/scripts/build/server/config.ts

@@ -75,7 +75,7 @@ function validateProductionEnv(envVars: Record<string, string>): void {
 }
 
 export interface LoadBuildConfigOptions {
-  compileOnly?: boolean
+  ci?: boolean
 }
 
 export function loadBuildConfig(
@@ -84,7 +84,9 @@ export function loadBuildConfig(
 ): BuildConfig {
   const fileEnv = loadProdEnv(rootDir)
   const envVars = buildInlineEnv(fileEnv)
-  validateProductionEnv(envVars)
+  if (!options.ci) {
+    validateProductionEnv(envVars)
+  }
 
   const processEnv: NodeJS.ProcessEnv = {
     PATH: process.env.PATH ?? '',
@@ -92,7 +94,7 @@ export function loadBuildConfig(
     ...process.env,
   }
 
-  if (options.compileOnly) {
+  if (options.ci) {
     return { version: readServerVersion(rootDir), envVars, processEnv }
   }
 

packages/browseros-agent/scripts/build/server/orchestrator.ts

@@ -2,13 +2,17 @@ import { existsSync } from 'node:fs'
 import { resolve } from 'node:path'
 
 import { log } from '../log'
-import { archiveAndUploadArtifacts } from './archive'
+import { archiveAndUploadArtifacts, archiveArtifacts } from './archive'
 import { parseBuildArgs } from './cli'
 import { compileServerBinaries, getDistProdRoot } from './compile'
 import { loadBuildConfig } from './config'
 import { getTargetRules, loadManifest } from './manifest'
 import { createR2Client } from './r2'
-import { stageTargetArtifact } from './stage'
+import { stageCompiledArtifact, stageTargetArtifact } from './stage'
+
+function buildModeLabel(ci: boolean): string {
+  return ci ? 'ci' : 'full'
+}
 
 export async function runProdResourceBuild(argv: string[]): Promise<void> {
   const rootDir = resolve(import.meta.dir, '../../..')
@@ -16,25 +20,40 @@ export async function runProdResourceBuild(argv: string[]): Promise<void> {
 
   const args = parseBuildArgs(argv)
 
-  const buildConfig = loadBuildConfig(rootDir, {
-    compileOnly: args.compileOnly,
-  })
+  const buildConfig = loadBuildConfig(rootDir, { ci: args.ci })
 
   log.header(`Building BrowserOS server artifacts v${buildConfig.version}`)
   log.info(`Targets: ${args.targets.map((target) => target.id).join(', ')}`)
-  log.info(`Mode: ${args.compileOnly ? 'compile-only' : 'full'}`)
+  log.info(`Mode: ${buildModeLabel(args.ci)}`)
 
   const compiled = await compileServerBinaries(
     args.targets,
     buildConfig.envVars,
     buildConfig.processEnv,
     buildConfig.version,
+    { ci: args.ci },
   )
 
-  if (args.compileOnly) {
-    log.done('Compile-only build completed')
+  if (args.ci) {
+    const distRoot = getDistProdRoot()
+    const localArtifacts = []
+
     for (const binary of compiled) {
-      log.info(`${binary.target.id}: ${binary.binaryPath}`)
+      log.step(`Packaging ${binary.target.name}`)
+      const staged = await stageCompiledArtifact(
+        distRoot,
+        binary.binaryPath,
+        binary.target,
+        buildConfig.version,
+      )
+      localArtifacts.push(staged)
+      log.success(`Packaged ${binary.target.id}`)
+    }
+
+    const archiveResults = await archiveArtifacts(localArtifacts)
+    log.done('CI build completed')
+    for (const result of archiveResults) {
+      log.info(`${result.targetId}: ${result.zipPath}`)
     }
     return
   }

packages/browseros-agent/scripts/build/server/stage.ts

@@ -32,6 +32,36 @@ async function copyServerBinary(
   }
 }
 
+async function createArtifactRoot(
+  distRoot: string,
+  compiledBinaryPath: string,
+  target: BuildTarget,
+): Promise<string> {
+  const rootDir = artifactRoot(distRoot, target)
+  await rm(rootDir, { recursive: true, force: true })
+  await mkdir(rootDir, { recursive: true })
+  await copyServerBinary(
+    compiledBinaryPath,
+    serverDestinationPath(rootDir, target),
+    target,
+  )
+  return rootDir
+}
+
+async function finalizeArtifact(
+  rootDir: string,
+  target: BuildTarget,
+  version: string,
+): Promise<StagedArtifact> {
+  const metadataPath = await writeArtifactMetadata(rootDir, target, version)
+  return {
+    target,
+    rootDir,
+    resourcesDir: join(rootDir, 'resources'),
+    metadataPath,
+  }
+}
+
 function resolveDestination(rootDir: string, destination: string): string {
   const outputPath = join(rootDir, destination)
   const relativePath = relative(rootDir, outputPath)
@@ -67,25 +97,21 @@ export async function stageTargetArtifact(
   r2: R2Config,
   version: string,
 ): Promise<StagedArtifact> {
-  const rootDir = artifactRoot(distRoot, target)
-  await rm(rootDir, { recursive: true, force: true })
-  await mkdir(rootDir, { recursive: true })
-
-  await copyServerBinary(
-    compiledBinaryPath,
-    serverDestinationPath(rootDir, target),
-    target,
-  )
+  const rootDir = await createArtifactRoot(distRoot, compiledBinaryPath, target)
 
   for (const rule of rules) {
     await stageRule(rootDir, rule, target, client, r2)
   }
 
-  const metadataPath = await writeArtifactMetadata(rootDir, target, version)
-  return {
-    target,
-    rootDir,
-    resourcesDir: join(rootDir, 'resources'),
-    metadataPath,
-  }
+  return finalizeArtifact(rootDir, target, version)
+}
+
+export async function stageCompiledArtifact(
+  distRoot: string,
+  compiledBinaryPath: string,
+  target: BuildTarget,
+  version: string,
+): Promise<StagedArtifact> {
+  const rootDir = await createArtifactRoot(distRoot, compiledBinaryPath, target)
+  return finalizeArtifact(rootDir, target, version)
 }

packages/browseros-agent/scripts/build/server/types.ts

@@ -21,7 +21,7 @@ export interface BuildArgs {
   targets: BuildTarget[]
   manifestPath: string
   upload: boolean
-  compileOnly: boolean
+  ci: boolean
 }
 
 export interface R2Config {

packages/browseros/build/cli/build.py

@@ -402,9 +402,11 @@ def main(
         "upload": upload,
     }
 
-    # Resolve build context (CONFIG mode or DIRECT mode)
+    # Resolve build context (CONFIG mode or DIRECT mode).
+    # Returns one Context per architecture — single-element for normal
+    # builds, multi-element when YAML declares `architecture: [x64, arm64]`.
     try:
-        ctx = resolve_config(cli_args, config_data)
+        arch_ctxs = resolve_config(cli_args, config_data)
     except ValueError as e:
         log_error(str(e))
         raise typer.Exit(1)
@@ -459,20 +461,40 @@ def main(
         os.environ["DEPOT_TOOLS_WIN_TOOLCHAIN"] = "0"
         log_info("Set DEPOT_TOOLS_WIN_TOOLCHAIN=0 for Windows build")
 
+    # Print build summary using the first context — versions and paths
+    # are identical across per-arch contexts. Architecture is logged again
+    # inside the loop below for multi-arch runs.
+    summary_ctx = arch_ctxs[0]
     log_info(f"📍 Root: {root_dir}")
-    log_info(f"📍 Chromium: {ctx.chromium_src}")
-    log_info(f"📍 Architecture: {ctx.architecture}")
-    log_info(f"📍 Build type: {ctx.build_type}")
-    log_info(f"📍 Output: {ctx.out_dir}")
-    log_info(f"📍 Semantic version: {ctx.semantic_version}")
-    log_info(f"📍 Chromium version: {ctx.chromium_version}")
-    log_info(f"📍 Build offset: {ctx.browseros_build_offset}")
+    log_info(f"📍 Chromium: {summary_ctx.chromium_src}")
+    if len(arch_ctxs) > 1:
+        log_info(
+            f"📍 Architectures: {[c.architecture for c in arch_ctxs]} (multi-arch loop)"
+        )
+    else:
+        log_info(f"📍 Architecture: {summary_ctx.architecture}")
+    log_info(f"📍 Build type: {summary_ctx.build_type}")
+    log_info(f"📍 Semantic version: {summary_ctx.semantic_version}")
+    log_info(f"📍 Chromium version: {summary_ctx.chromium_version}")
+    log_info(f"📍 Build offset: {summary_ctx.browseros_build_offset}")
     log_info(f"📍 Pipeline: {' → '.join(pipeline)}")
     log_info("=" * 70)
 
-    # Set notification context for OS and architecture
     os_name = "macOS" if IS_MACOS() else "Windows" if IS_WINDOWS() else "Linux"
-    set_build_context(os_name, ctx.architecture)
 
-    # Execute pipeline
-    execute_pipeline(ctx, pipeline, AVAILABLE_MODULES, pipeline_name="build")
+    # Execute the pipeline once per architecture. Modules see a normal
+    # single-arch ctx; the runner is the only thing that knows about the
+    # multi-arch loop.
+    for i, arch_ctx in enumerate(arch_ctxs, start=1):
+        if len(arch_ctxs) > 1:
+            log_info("\n" + "#" * 70)
+            log_info(
+                f"# Architecture {i}/{len(arch_ctxs)}: {arch_ctx.architecture}"
+            )
+            log_info(f"# Output: {arch_ctx.out_dir}")
+            log_info("#" * 70)
+
+        set_build_context(os_name, arch_ctx.architecture)
+        execute_pipeline(
+            arch_ctx, pipeline, AVAILABLE_MODULES, pipeline_name="build"
+        )

packages/browseros/build/common/resolver.py

@@ -26,11 +26,13 @@ from .context import Context
 from .env import EnvConfig
 from .utils import get_platform_arch, log_info
 
+VALID_ARCHITECTURES = {"x64", "arm64", "universal"}
+
 
 def resolve_config(
     cli_args: Dict[str, Any],
     yaml_config: Optional[Dict[str, Any]] = None,
-) -> Context:
+) -> List[Context]:
     """Resolve build configuration - single entry point.
 
     Args:
@@ -38,7 +40,9 @@ def resolve_config(
         yaml_config: Optional YAML configuration (triggers CONFIG mode)
 
     Returns:
-        Fully resolved Context object
+        List of fully resolved Context objects. Single-element for the
+        common single-arch case; multi-element when YAML declares
+        `architecture: [x64, arm64]` (Linux multi-arch).
 
     Raises:
         ValueError: If required fields missing or invalid
@@ -59,7 +63,7 @@ def resolve_config(
 
 def _resolve_config_mode(
     yaml_config: Dict[str, Any], cli_args: Dict[str, Any]
-) -> Context:
+) -> List[Context]:
     """CONFIG MODE: YAML is base, CLI can override.
 
     Args:
@@ -67,7 +71,7 @@ def _resolve_config_mode(
         cli_args: CLI arguments (can override YAML values)
 
     Returns:
-        Context with values from YAML, optionally overridden by CLI
+        List of Contexts. One per architecture when YAML provides a list.
 
     Raises:
         ValueError: If required fields missing from both YAML and CLI
@@ -94,41 +98,66 @@ def _resolve_config_mode(
             f"Expected directory with Chromium source code"
         )
 
-    # architecture: CLI override > YAML > platform default
-    architecture = (
-        cli_args.get("arch")
-        or build_section.get("architecture")
-        or build_section.get("arch")
-    )
-    arch_source = "cli" if cli_args.get("arch") else "yaml"
-    if not architecture:
-        architecture = get_platform_arch()
+    # architecture: CLI override > YAML > platform default.
+    # YAML may be a string OR a list (e.g. [x64, arm64]) — list form runs
+    # the entire pipeline once per arch.
+    cli_arch = cli_args.get("arch")
+    yaml_arch = build_section.get("architecture") or build_section.get("arch")
+
+    if cli_arch:
+        architectures = [cli_arch]
+        arch_source = "cli"
+    elif yaml_arch is not None:
+        architectures = yaml_arch if isinstance(yaml_arch, list) else [yaml_arch]
+        arch_source = "yaml"
+    else:
+        architectures = [get_platform_arch()]
         arch_source = "default"
-        log_info(f"CONFIG MODE: Using platform default architecture: {architecture}")
+        log_info(
+            f"CONFIG MODE: Using platform default architecture: {architectures[0]}"
+        )
+
+    for arch in architectures:
+        if arch not in VALID_ARCHITECTURES:
+            raise ValueError(
+                f"CONFIG MODE: invalid architecture '{arch}'. "
+                f"Valid: {sorted(VALID_ARCHITECTURES)}"
+            )
 
     # build_type: CLI override > YAML > debug
     build_type = cli_args.get("build_type") or build_section.get("type", "debug")
     build_type_source = "cli" if cli_args.get("build_type") else "yaml"
 
     log_info(f"✓ CONFIG MODE: chromium_src={chromium_src} ({chromium_src_source})")
-    log_info(f"✓ CONFIG MODE: architecture={architecture} ({arch_source})")
+    if len(architectures) > 1:
+        log_info(
+            f"✓ CONFIG MODE: architectures={architectures} ({arch_source}, multi-arch loop)"
+        )
+    else:
+        log_info(
+            f"✓ CONFIG MODE: architecture={architectures[0]} ({arch_source})"
+        )
     log_info(f"✓ CONFIG MODE: build_type={build_type} ({build_type_source})")
 
-    return Context(
-        chromium_src=chromium_src,
-        architecture=architecture,
-        build_type=build_type,
-    )
+    return [
+        Context(
+            chromium_src=chromium_src,
+            architecture=arch,
+            build_type=build_type,
+        )
+        for arch in architectures
+    ]
 
 
-def _resolve_direct_mode(cli_args: Dict[str, Any]) -> Context:
+def _resolve_direct_mode(cli_args: Dict[str, Any]) -> List[Context]:
     """DIRECT MODE: CLI > Env > Defaults.
 
     Args:
         cli_args: CLI arguments (None if not provided by user)
 
     Returns:
-        Context with resolved values
+        Single-element list with the resolved Context. DIRECT mode is
+        always single-arch (CLI --arch is a scalar).
 
     Raises:
         ValueError: If chromium_src not provided
@@ -160,6 +189,12 @@ def _resolve_direct_mode(cli_args: Dict[str, Any]) -> Context:
         architecture = get_platform_arch()
         log_info(f"DIRECT MODE: Using platform default architecture: {architecture}")
 
+    if architecture not in VALID_ARCHITECTURES:
+        raise ValueError(
+            f"DIRECT MODE: invalid architecture '{architecture}'. "
+            f"Valid: {sorted(VALID_ARCHITECTURES)}"
+        )
+
     # build_type: CLI > Default
     build_type = cli_args.get("build_type") or "debug"
 
@@ -167,11 +202,13 @@ def _resolve_direct_mode(cli_args: Dict[str, Any]) -> Context:
     log_info(f"✓ DIRECT MODE: architecture={architecture} (cli/env/default)")
     log_info(f"✓ DIRECT MODE: build_type={build_type} (cli/default)")
 
-    return Context(
-        chromium_src=chromium_src,
-        architecture=architecture,
-        build_type=build_type,
-    )
+    return [
+        Context(
+            chromium_src=chromium_src,
+            architecture=architecture,
+            build_type=build_type,
+        )
+    ]
 
 
 def resolve_pipeline(

packages/browseros/build/config/package.linux.yaml

@@ -3,7 +3,10 @@
 # This config packages an already-built Linux application.
 # Use this when you have a pre-built app and only need to package it.
 #
-# Expects: out/Default/chrome (Linux binary)
+# Expects: out/Default_<arch>/browseros
+# Invoke with:
+#   browseros build --config build/config/package.linux.yaml --arch x64
+#   browseros build --config build/config/package.linux.yaml --arch arm64
 #
 # Environment Variables:
 #   Use !env tag to reference environment variables:
@@ -11,7 +14,6 @@
 
 build:
   type: release
-  architecture: x64  # Linux x64
 
 gn_flags:
   file: build/config/gn/flags.linux.release.gn

packages/browseros/build/config/release.linux.yaml

@@ -1,17 +1,24 @@
 # BrowserOS Linux Release Build Configuration
 #
+# Pinned to arm64-only to validate the cross-compile sysroot bootstrap
+# end-to-end on a Linux x64 host. Flip back to `[x64, arm64]` once arm64
+# is green.
+#
+# Run:
+#   browseros build --config build/config/release.linux.yaml
+#
 # Environment Variables:
 #   Use !env tag to reference environment variables:
 #     Example: chromium_src: !env CHROMIUM_SRC
 
 build:
   type: release
-  architecture: x64  # Linux x64
+  architecture: arm64
 
 gn_flags:
   file: build/config/gn/flags.linux.release.gn
 
-# Explicit module execution order
+# Explicit module execution order. Runs once per architecture above.
 modules:
   # Phase 1: Setup
   - clean

packages/browseros/build/modules/package/linux.py

@@ -17,10 +17,64 @@ from ...common.utils import (
     run_command,
     safe_rmtree,
     join_paths,
+    get_platform_arch,
     IS_LINUX,
 )
 from ...common.notify import get_notifier, COLOR_GREEN
 
+# Target-arch packaging metadata. These describe the artifact we're
+# producing, not the build machine. `appimage_arch` is passed to
+# appimagetool via the ARCH env var; `deb_arch` is written into the
+# .deb control file.
+LINUX_ARCHITECTURE_CONFIG = {
+    "x64": {
+        "appimage_arch": "x86_64",
+        "deb_arch": "amd64",
+    },
+    "arm64": {
+        "appimage_arch": "aarch64",
+        "deb_arch": "arm64",
+    },
+}
+
+# Host-arch tool selection. appimagetool is a normal binary that runs on
+# the build machine — when cross-compiling arm64 from an x64 host, we
+# still need the x86_64 tool to actually execute. Keyed on
+# get_platform_arch() (BUILD machine arch), NOT ctx.architecture.
+LINUX_HOST_APPIMAGETOOL = {
+    "x64": (
+        "appimagetool-x86_64.AppImage",
+        "https://github.com/AppImage/AppImageKit/releases/download/continuous/appimagetool-x86_64.AppImage",
+    ),
+    "arm64": (
+        "appimagetool-aarch64.AppImage",
+        "https://github.com/AppImage/AppImageKit/releases/download/continuous/appimagetool-aarch64.AppImage",
+    ),
+}
+
+
+def get_linux_architecture_config(architecture: str) -> dict[str, str]:
+    config = LINUX_ARCHITECTURE_CONFIG.get(architecture)
+    if not config:
+        supported = ", ".join(sorted(LINUX_ARCHITECTURE_CONFIG))
+        raise ValueError(
+            f"Unsupported Linux architecture: {architecture}. Supported: {supported}"
+        )
+    return config
+
+
+def get_host_appimagetool() -> tuple[str, str]:
+    """Return (filename, url) for the appimagetool binary that runs on
+    the current build machine. Critical for cross-compile correctness."""
+    host_arch = get_platform_arch()
+    tool = LINUX_HOST_APPIMAGETOOL.get(host_arch)
+    if not tool:
+        supported = ", ".join(sorted(LINUX_HOST_APPIMAGETOOL))
+        raise ValueError(
+            f"No appimagetool binary for host arch '{host_arch}'. Supported: {supported}"
+        )
+    return tool
+
 
 class LinuxPackageModule(CommandModule):
     produces = ["appimage", "deb"]
@@ -30,6 +84,10 @@ class LinuxPackageModule(CommandModule):
     def validate(self, ctx: Context) -> None:
         if not IS_LINUX():
             raise ValidationError("Linux packaging requires Linux")
+        try:
+            get_linux_architecture_config(ctx.architecture)
+        except ValueError as exc:
+            raise ValidationError(str(exc)) from exc
 
         out_dir = join_paths(ctx.chromium_src, ctx.out_dir)
         chrome_binary = join_paths(out_dir, ctx.BROWSEROS_APP_NAME)
@@ -73,7 +131,7 @@ class LinuxPackageModule(CommandModule):
             artifacts.append(deb_path.name)
         notifier.notify(
             "📦 Package Created",
-            f"Linux packages created successfully",
+            "Linux packages created successfully",
             {
                 "Artifacts": ", ".join(artifacts),
                 "Version": ctx.semantic_version,
@@ -284,25 +342,30 @@ export CHROME_WRAPPER="${{THIS}}"
 
 
 def download_appimagetool(ctx: Context) -> Optional[Path]:
-    """Download appimagetool if not available"""
+    """Download the appimagetool binary that runs on the build machine.
+
+    Note: this is keyed on the HOST arch, not ctx.architecture. When
+    cross-compiling arm64 packages from an x64 host, we still need the
+    x86_64 appimagetool because the tool executes locally; the target
+    arch is communicated via the ARCH env var in create_appimage().
+    """
     tool_dir = Path(join_paths(ctx.root_dir, "build", "tools"))
     tool_dir.mkdir(exist_ok=True)
 
-    tool_path = Path(join_paths(tool_dir, "appimagetool-x86_64.AppImage"))
+    tool_filename, url = get_host_appimagetool()
+    tool_path = Path(join_paths(tool_dir, tool_filename))
 
     if tool_path.exists():
-        log_info("✓ appimagetool already available")
+        log_info(f"✓ appimagetool already available ({tool_filename})")
         return tool_path
 
-    log_info("📥 Downloading appimagetool...")
-    url = "https://github.com/AppImage/AppImageKit/releases/download/continuous/appimagetool-x86_64.AppImage"
-
+    log_info(f"📥 Downloading {tool_filename}...")
     cmd = ["wget", "-O", str(tool_path), url]
     result = run_command(cmd, check=False)
 
     if result.returncode == 0:
         tool_path.chmod(0o755)
-        log_success("✓ Downloaded appimagetool")
+        log_success(f"✓ Downloaded {tool_filename}")
         return tool_path
     else:
         log_error("Failed to download appimagetool")
@@ -312,6 +375,7 @@ def download_appimagetool(ctx: Context) -> Optional[Path]:
 def create_appimage(ctx: Context, appdir: Path, output_path: Path) -> bool:
     """Create AppImage from AppDir"""
     log_info("📦 Creating AppImage...")
+    arch_config = get_linux_architecture_config(ctx.architecture)
 
     # Download appimagetool if needed
     appimagetool = download_appimagetool(ctx)
@@ -319,7 +383,7 @@ def create_appimage(ctx: Context, appdir: Path, output_path: Path) -> bool:
         return False
 
     # Set architecture environment variable (required by appimagetool)
-    arch = "x86_64" if ctx.architecture == "x64" else "aarch64"
+    arch = arch_config["appimage_arch"]
 
     # Create AppImage with ARCH env var set for this command only
     cmd = [
@@ -384,7 +448,7 @@ def create_control_file(ctx: Context, debian_dir: Path) -> None:
     version = version.lstrip("v").replace(" ", "").replace("_", ".")
 
     # Architecture mapping
-    deb_arch = "amd64" if ctx.architecture == "x64" else "arm64"
+    deb_arch = get_linux_architecture_config(ctx.architecture)["deb_arch"]
 
     control_content = f"""Package: browseros
 Version: {version}
@@ -653,7 +717,9 @@ def package_appimage(ctx: Context, package_dir: Path) -> Optional[Path]:
     """
     log_info("🖼️  Building AppImage...")
 
-    appdir = Path(join_paths(package_dir, f"{ctx.BROWSEROS_APP_BASE_NAME}.AppDir"))
+    appdir = Path(
+        join_paths(package_dir, f"{ctx.BROWSEROS_APP_BASE_NAME}-{ctx.architecture}.AppDir")
+    )
     if appdir.exists():
         safe_rmtree(appdir)
 
@@ -683,7 +749,9 @@ def package_deb(ctx: Context, package_dir: Path) -> Optional[Path]:
     """
     log_info("📦 Building .deb package...")
 
-    debdir = Path(join_paths(package_dir, f"{ctx.BROWSEROS_APP_BASE_NAME}_deb"))
+    debdir = Path(
+        join_paths(package_dir, f"{ctx.BROWSEROS_APP_BASE_NAME}_{ctx.architecture}_deb")
+    )
     if debdir.exists():
         safe_rmtree(debdir)
 
@@ -703,6 +771,8 @@ def package_deb(ctx: Context, package_dir: Path) -> Optional[Path]:
         return output_path
 
     return None
+
+
 def package_universal(contexts: List[Context]) -> bool:
     """Linux doesn't support universal binaries"""
     log_warning("Universal binaries are not supported on Linux")

packages/browseros/build/modules/package/linux_test.py

@@ -0,0 +1,63 @@
+#!/usr/bin/env python3
+"""Tests for Linux packaging architecture helpers."""
+
+import unittest
+from unittest.mock import patch
+
+from build.modules.package.linux import (
+    LINUX_HOST_APPIMAGETOOL,
+    get_host_appimagetool,
+    get_linux_architecture_config,
+)
+
+
+class LinuxArchitectureConfigTest(unittest.TestCase):
+    def test_returns_x64_packaging_config(self) -> None:
+        config = get_linux_architecture_config("x64")
+
+        self.assertEqual(config["appimage_arch"], "x86_64")
+        self.assertEqual(config["deb_arch"], "amd64")
+
+    def test_returns_arm64_packaging_config(self) -> None:
+        config = get_linux_architecture_config("arm64")
+
+        self.assertEqual(config["appimage_arch"], "aarch64")
+        self.assertEqual(config["deb_arch"], "arm64")
+
+    def test_rejects_unsupported_architecture(self) -> None:
+        with self.assertRaisesRegex(ValueError, "Unsupported Linux architecture"):
+            get_linux_architecture_config("universal")
+
+
+class HostAppImageToolTest(unittest.TestCase):
+    """The appimagetool binary must match the BUILD machine's arch, not
+    the target arch — otherwise cross-compiling arm64 packages from an x64
+    host fails because the aarch64 tool can't execute on x64."""
+
+    def test_x64_host_picks_x86_64_tool(self) -> None:
+        with patch(
+            "build.modules.package.linux.get_platform_arch", return_value="x64"
+        ):
+            filename, url = get_host_appimagetool()
+
+        self.assertEqual(filename, "appimagetool-x86_64.AppImage")
+        self.assertIn("x86_64", url)
+
+    def test_arm64_host_picks_aarch64_tool(self) -> None:
+        with patch(
+            "build.modules.package.linux.get_platform_arch", return_value="arm64"
+        ):
+            filename, url = get_host_appimagetool()
+
+        self.assertEqual(filename, "appimagetool-aarch64.AppImage")
+        self.assertIn("aarch64", url)
+
+    def test_host_lookup_independent_of_target(self) -> None:
+        # Both architectures must be present in the host lookup so cross
+        # builds work in either direction.
+        self.assertIn("x64", LINUX_HOST_APPIMAGETOOL)
+        self.assertIn("arm64", LINUX_HOST_APPIMAGETOOL)
+
+
+if __name__ == "__main__":
+    unittest.main()

packages/browseros/build/modules/release/common.py

@@ -6,7 +6,6 @@ from datetime import datetime
 from typing import Dict, List, Optional
 
 from ...common.env import EnvConfig
-from ...common.utils import log_warning
 from ..storage import get_release_json, get_r2_client, BOTO3_AVAILABLE
 
 PLATFORMS = ["macos", "win", "linux"]
@@ -24,6 +23,8 @@ DOWNLOAD_PATH_MAPPING = {
     "linux": {
         "x64_appimage": "download/BrowserOS.AppImage",
         "x64_deb": "download/BrowserOS.deb",
+        "arm64_appimage": "download/BrowserOS-arm64.AppImage",
+        "arm64_deb": "download/BrowserOS-arm64.deb",
     },
 }
 

packages/browseros/build/modules/setup/configure.py

@@ -1,9 +1,19 @@
 #!/usr/bin/env python3
 """Build configuration module for BrowserOS build system"""
 
+import sys
+
 from ...common.module import CommandModule, ValidationError
 from ...common.context import Context
-from ...common.utils import run_command, log_info, log_success, join_paths, IS_WINDOWS
+from ...common.utils import (
+    run_command,
+    log_info,
+    log_warning,
+    log_success,
+    join_paths,
+    IS_LINUX,
+    IS_WINDOWS,
+)
 
 
 class ConfigureModule(CommandModule):
@@ -25,6 +35,16 @@ class ConfigureModule(CommandModule):
     def execute(self, ctx: Context) -> None:
         log_info(f"\n⚙️  Configuring {ctx.build_type} build for {ctx.architecture}...")
 
+        # Linux: ensure the target-arch Debian sysroot is installed before
+        # `gn gen`. sysroot.gni asserts on missing sysroots, and relying on
+        # `gclient sync` DEPS hooks is fragile — the hook only fires when
+        # .gclient declared the right `target_cpus` *before* sync, which
+        # isn't guaranteed for chromium_src checkouts that predate
+        # cross-arch support. install-sysroot.py is idempotent and fast,
+        # so call it unconditionally for the target arch.
+        if IS_LINUX():
+            self._ensure_linux_sysroot(ctx)
+
         out_path = join_paths(ctx.chromium_src, ctx.out_dir)
         out_path.mkdir(parents=True, exist_ok=True)
 
@@ -43,3 +63,26 @@ class ConfigureModule(CommandModule):
         run_command(gn_args, cwd=ctx.chromium_src)
 
         log_success("Build configured")
+
+    def _ensure_linux_sysroot(self, ctx: Context) -> None:
+        install_script = (
+            ctx.chromium_src / "build" / "linux" / "sysroot_scripts" / "install-sysroot.py"
+        )
+        if not install_script.exists():
+            log_warning(
+                f"⚠️  install-sysroot.py not found at {install_script}; "
+                f"skipping sysroot bootstrap. gn gen will fail if the "
+                f"{ctx.architecture} sysroot is missing."
+            )
+            return
+
+        # install-sysroot.py accepts our arch names directly: it translates
+        # `x64`→`amd64` internally via ARCH_TRANSLATIONS, and `arm64` is a
+        # valid pass-through value.
+        log_info(
+            f"📦 Ensuring Linux sysroot for {ctx.architecture} (idempotent)..."
+        )
+        run_command(
+            [sys.executable, str(install_script), f"--arch={ctx.architecture}"],
+            cwd=ctx.chromium_src,
+        )

packages/browseros/build/modules/setup/git.py

@@ -1,12 +1,24 @@
 #!/usr/bin/env python3
 """Git operations module for BrowserOS build system"""
 
+import re
 import subprocess
 import tarfile
 import urllib.request
+from typing import List
+
 from ...common.module import CommandModule, ValidationError
 from ...common.context import Context
-from ...common.utils import run_command, log_info, log_error, log_success, IS_WINDOWS, safe_rmtree
+from ...common.utils import (
+    run_command,
+    log_info,
+    log_warning,
+    log_error,
+    log_success,
+    IS_LINUX,
+    IS_WINDOWS,
+    safe_rmtree,
+)
 
 
 class GitSetupModule(CommandModule):
@@ -32,6 +44,12 @@ class GitSetupModule(CommandModule):
         log_info(f"🔀 Checking out tag: {ctx.chromium_version}")
         run_command(["git", "checkout", f"tags/{ctx.chromium_version}"], cwd=ctx.chromium_src)
 
+        # On Linux, depot_tools fetches per-arch sysroots automatically when
+        # `.gclient` declares `target_cpus`. Ensure both x64 and arm64 are
+        # listed before sync so cross-compilation just works on x64 hosts.
+        if IS_LINUX():
+            self._ensure_gclient_target_cpus(ctx, ["x64", "arm64"])
+
         log_info("📥 Syncing dependencies (this may take a while)...")
         if IS_WINDOWS():
             run_command(["gclient.bat", "sync", "-D", "--no-history", "--shallow"], cwd=ctx.chromium_src)
@@ -40,6 +58,49 @@ class GitSetupModule(CommandModule):
 
         log_success("Git setup complete")
 
+    def _ensure_gclient_target_cpus(self, ctx: Context, required: List[str]) -> None:
+        """Idempotently add `target_cpus` to .gclient so depot_tools fetches
+        the matching Linux sysroots for cross-compilation.
+
+        depot_tools convention: .gclient lives one directory above
+        chromium_src (i.e. ../.gclient). It is a Python file with a list
+        of solution dicts followed by optional top-level assignments.
+        We append a `target_cpus = [...]` line if missing or merge in any
+        archs that aren't already present.
+        """
+        gclient_path = ctx.chromium_src.parent / ".gclient"
+        if not gclient_path.exists():
+            log_warning(
+                f"⚠️  .gclient not found at {gclient_path}; "
+                f"skipping target_cpus bootstrap. "
+                f"Cross-arch builds may fail until you run `fetch chromium`."
+            )
+            return
+
+        content = gclient_path.read_text()
+        match = re.search(r"^\s*target_cpus\s*=\s*\[([^\]]*)\]", content, re.MULTILINE)
+
+        if match:
+            existing = re.findall(r"['\"]([^'\"]+)['\"]", match.group(1))
+            missing = [arch for arch in required if arch not in existing]
+            if not missing:
+                log_info(f"✓ .gclient target_cpus already includes {required}")
+                return
+            merged = sorted(set(existing) | set(required))
+            new_line = f"target_cpus = {merged!r}"
+            content = (
+                content[: match.start()] + new_line + content[match.end() :]
+            )
+            log_info(
+                f"📝 Updating .gclient target_cpus: {existing} → {merged}"
+            )
+        else:
+            new_line = f"\ntarget_cpus = {required!r}\n"
+            content = content.rstrip() + "\n" + new_line
+            log_info(f"📝 Adding target_cpus = {required} to .gclient")
+
+        gclient_path.write_text(content)
+
     def _verify_tag_exists(self, ctx: Context) -> None:
         result = subprocess.run(
             ["git", "tag", "-l", ctx.chromium_version],

packages/browseros/build/modules/storage/upload.py

@@ -4,7 +4,7 @@
 import json
 from datetime import datetime, timezone
 from pathlib import Path
-from typing import Dict, List, Optional, Tuple
+from typing import Any, Dict, List, Optional, Tuple, cast
 
 from ...common.module import CommandModule, ValidationError
 from ...common.context import Context
@@ -21,6 +21,7 @@ from ...common.notify import get_notifier, COLOR_GREEN
 from .r2 import (
     BOTO3_AVAILABLE,
     get_r2_client,
+    get_release_json,
     upload_file_to_r2,
 )
 
@@ -58,7 +59,10 @@ class UploadModule(CommandModule):
         log_info("\nUploading package artifacts to R2...")
 
         extra_metadata = {}
-        sparkle_signatures = ctx.artifacts.get("sparkle_signatures")
+        sparkle_signatures = cast(
+            Optional[dict[str, tuple[str, int]]],
+            ctx.artifacts.get("sparkle_signatures"),
+        )
         if sparkle_signatures:
             for filename, (sig, length) in sparkle_signatures.items():
                 extra_metadata[filename] = {
@@ -120,6 +124,36 @@ def generate_release_json(
     return release_data
 
 
+def merge_release_metadata(existing: Optional[Dict], new: Dict) -> Dict:
+    if not existing:
+        return new
+
+    merged = dict(existing)
+    merged.update({key: value for key, value in new.items() if key != "artifacts"})
+
+    artifacts = dict(existing.get("artifacts", {}))
+    artifacts.update(new.get("artifacts", {}))
+    merged["artifacts"] = artifacts
+    return merged
+
+
+def _get_linux_artifact_key(filename: str) -> Optional[str]:
+    lower = filename.lower()
+
+    if ".appimage" in lower:
+        if "arm64" in lower or "aarch64" in lower:
+            return "arm64_appimage"
+        if "x64" in lower or "x86_64" in lower:
+            return "x64_appimage"
+    elif ".deb" in lower:
+        if "arm64" in lower or "aarch64" in lower:
+            return "arm64_deb"
+        if "amd64" in lower or "x64" in lower or "x86_64" in lower:
+            return "x64_deb"
+
+    return None
+
+
 def _get_artifact_key(filename: str, platform: str) -> str:
     """Get artifact key name from filename
 
@@ -147,10 +181,10 @@ def _get_artifact_key(filename: str, platform: str) -> str:
             return "x64_zip"
 
     elif platform == "linux":
-        if ".appimage" in lower:
-            return "x64_appimage"
-        elif ".deb" in lower:
-            return "x64_deb"
+        artifact_key = _get_linux_artifact_key(filename)
+        if artifact_key:
+            return artifact_key
+        log_warning(f"Unrecognized Linux artifact name: {filename}; using stem key")
 
     return Path(filename).stem
 
@@ -181,7 +215,7 @@ def detect_artifacts(ctx: Context) -> List[Path]:
 
 def upload_release_artifacts(
     ctx: Context,
-    extra_metadata: Optional[Dict[str, Dict[str, any]]] = None,
+    extra_metadata: Optional[Dict[str, Dict[str, Any]]] = None,
 ) -> Tuple[bool, Optional[Dict]]:
     """Upload release artifacts to R2 and generate release.json
 
@@ -240,6 +274,13 @@ def upload_release_artifacts(
         artifact_metadata.append(metadata)
 
     release_data = generate_release_json(ctx, artifact_metadata, platform)
+    if platform == "linux":
+        # Linux x64 and arm64 release jobs must be sequenced. A parallel
+        # fetch-merge-upload flow can still race and drop one architecture.
+        existing_release_data = get_release_json(
+            ctx.get_semantic_version(), platform, env
+        )
+        release_data = merge_release_metadata(existing_release_data, release_data)
     release_json_path = ctx.get_dist_dir() / "release.json"
     release_json_path.write_text(json.dumps(release_data, indent=2))
 
@@ -248,7 +289,7 @@ def upload_release_artifacts(
         return False, None
 
     log_success(f"\nSuccessfully uploaded {len(artifacts)} artifact(s) to R2")
-    log_info(f"\nRelease metadata:")
+    log_info("\nRelease metadata:")
     log_info(f"  Version: {release_data['version']}")
     if platform == "macos":
         log_info(f"  Sparkle version: {release_data.get('sparkle_version', 'N/A')}")

packages/browseros/build/modules/storage/upload_test.py

@@ -0,0 +1,85 @@
+#!/usr/bin/env python3
+"""Tests for release artifact upload metadata helpers."""
+
+import unittest
+
+from build.modules.storage.upload import _get_artifact_key, merge_release_metadata
+
+
+class UploadMetadataTest(unittest.TestCase):
+    def test_linux_x64_artifacts_use_x64_keys(self) -> None:
+        self.assertEqual(
+            _get_artifact_key("BrowserOS_v1.2.3_x64.AppImage", "linux"),
+            "x64_appimage",
+        )
+        self.assertEqual(
+            _get_artifact_key("BrowserOS_v1.2.3_amd64.deb", "linux"),
+            "x64_deb",
+        )
+
+    def test_linux_arm64_artifacts_use_arm64_keys(self) -> None:
+        self.assertEqual(
+            _get_artifact_key("BrowserOS_v1.2.3_arm64.AppImage", "linux"),
+            "arm64_appimage",
+        )
+        self.assertEqual(
+            _get_artifact_key("BrowserOS_v1.2.3_arm64.deb", "linux"),
+            "arm64_deb",
+        )
+        self.assertEqual(
+            _get_artifact_key("BrowserOS_v1.2.3_aarch64.deb", "linux"),
+            "arm64_deb",
+        )
+
+    def test_merge_release_metadata_preserves_existing_artifacts(self) -> None:
+        existing = {
+            "platform": "linux",
+            "version": "1.2.3",
+            "build_date": "old",
+            "artifacts": {
+                "x64_appimage": {"filename": "BrowserOS_v1.2.3_x64.AppImage"},
+                "x64_deb": {"filename": "BrowserOS_v1.2.3_amd64.deb"},
+            },
+        }
+        new = {
+            "platform": "linux",
+            "version": "1.2.3",
+            "build_date": "new",
+            "artifacts": {
+                "arm64_appimage": {"filename": "BrowserOS_v1.2.3_arm64.AppImage"},
+                "arm64_deb": {"filename": "BrowserOS_v1.2.3_arm64.deb"},
+            },
+        }
+
+        merged = merge_release_metadata(existing, new)
+
+        self.assertEqual(merged["build_date"], "new")
+        self.assertEqual(
+            sorted(merged["artifacts"]),
+            ["arm64_appimage", "arm64_deb", "x64_appimage", "x64_deb"],
+        )
+
+    def test_merge_release_metadata_overwrites_matching_artifact_keys(self) -> None:
+        existing = {
+            "platform": "linux",
+            "version": "1.2.3",
+            "artifacts": {
+                "x64_appimage": {"filename": "old.AppImage", "size": 1},
+            },
+        }
+        new = {
+            "platform": "linux",
+            "version": "1.2.3",
+            "artifacts": {
+                "x64_appimage": {"filename": "new.AppImage", "size": 2},
+            },
+        }
+
+        merged = merge_release_metadata(existing, new)
+
+        self.assertEqual(merged["artifacts"]["x64_appimage"]["filename"], "new.AppImage")
+        self.assertEqual(merged["artifacts"]["x64_appimage"]["size"], 2)
+
+
+if __name__ == "__main__":
+    unittest.main()

packages/browseros/chromium_patches/chrome/browser/browseros/extensions/browseros_extension_loader.cc

@@ -1,9 +1,9 @@
 diff --git a/chrome/browser/browseros/extensions/browseros_extension_loader.cc b/chrome/browser/browseros/extensions/browseros_extension_loader.cc
 new file mode 100644
-index 0000000000000..e61b45d08b7e2
+index 0000000000000..fdb6be443f25b
 --- /dev/null
 +++ b/chrome/browser/browseros/extensions/browseros_extension_loader.cc
-@@ -0,0 +1,226 @@
+@@ -0,0 +1,269 @@
 +// Copyright 2024 The Chromium Authors
 +// Use of this source code is governed by a BSD-style license that can be
 +// found in the LICENSE file.
@@ -89,10 +89,53 @@ index 0000000000000..e61b45d08b7e2
 +  extension_ids_.merge(result.extension_ids);
 +  last_config_ = std::move(result.config);
 +
-+  LoadFinished(std::move(result.prefs));
++  base::DictValue prefs_to_load = std::move(result.prefs);
++
++  if (prefs_to_load.empty()) {
++    LOG(WARNING) << "browseros: Install returned empty prefs, "
++                 << "reconstructing from installed extensions";
++    prefs_to_load = ReconstructPrefsFromInstalledExtensions();
++    LOG(INFO) << "browseros: Reconstructed prefs for "
++              << prefs_to_load.size() << " installed extensions";
++  }
++
++  LoadFinished(std::move(prefs_to_load));
 +  OnStartupComplete(result.from_bundled);
 +}
 +
++base::DictValue
++BrowserOSExtensionLoader::ReconstructPrefsFromInstalledExtensions() {
++  base::DictValue prefs;
++
++  extensions::ExtensionRegistry* registry =
++      extensions::ExtensionRegistry::Get(profile_);
++  if (!registry) {
++    return prefs;
++  }
++
++  const std::string update_url =
++      base::FeatureList::IsEnabled(features::kBrowserOsAlphaFeatures)
++          ? kBrowserOSAlphaUpdateUrl
++          : kBrowserOSUpdateUrl;
++
++  for (const std::string& id : GetBrowserOSExtensionIds()) {
++    const extensions::Extension* ext = registry->GetInstalledExtension(id);
++    if (!ext) {
++      continue;
++    }
++
++    base::DictValue ext_pref;
++    ext_pref.Set(extensions::ExternalProviderImpl::kExternalUpdateUrl,
++                 update_url);
++    prefs.Set(id, std::move(ext_pref));
++
++    LOG(INFO) << "browseros: Reconstructed pref for installed extension "
++              << id << " v" << ext->version().GetString();
++  }
++
++  return prefs;
++}
++
 +const base::FilePath BrowserOSExtensionLoader::GetBaseCrxFilePath() {
 +  return bundled_crx_base_path_;
 +}

packages/browseros/chromium_patches/chrome/browser/browseros/extensions/browseros_extension_loader.h

@@ -1,9 +1,9 @@
 diff --git a/chrome/browser/browseros/extensions/browseros_extension_loader.h b/chrome/browser/browseros/extensions/browseros_extension_loader.h
 new file mode 100644
-index 0000000000000..2a14e9068156e
+index 0000000000000..ea2c856556f5f
 --- /dev/null
 +++ b/chrome/browser/browseros/extensions/browseros_extension_loader.h
-@@ -0,0 +1,81 @@
+@@ -0,0 +1,86 @@
 +// Copyright 2024 The Chromium Authors
 +// Use of this source code is governed by a BSD-style license that can be
 +// found in the LICENSE file.
@@ -62,6 +62,11 @@ index 0000000000000..2a14e9068156e
 +  // Convergence point for both startup paths.
 +  void OnStartupComplete(bool from_bundled);
 +
++  // Reconstructs minimal prefs from already-installed BrowserOS extensions.
++  // Used as a fallback when both bundled CRX and remote config fail,
++  // preventing orphan detection from uninstalling existing extensions.
++  base::DictValue ReconstructPrefsFromInstalledExtensions();
++
 +  // Installs remote extensions immediately via PendingExtensionManager + updater.
 +  void InstallRemoteExtensionsNow(base::DictValue config);
 +

packages/browseros/chromium_patches/chrome/browser/browseros/extensions/browseros_extension_maintainer.cc

@@ -1,6 +1,6 @@
 diff --git a/chrome/browser/browseros/extensions/browseros_extension_maintainer.cc b/chrome/browser/browseros/extensions/browseros_extension_maintainer.cc
 new file mode 100644
-index 0000000000000..bb33ae5d3b156
+index 0000000000000..5804d54696e8f
 --- /dev/null
 +++ b/chrome/browser/browseros/extensions/browseros_extension_maintainer.cc
 @@ -0,0 +1,395 @@

packages/browseros/chromium_patches/chrome/browser/devtools/protocol/browser_handler.cc

@@ -1,8 +1,13 @@
 diff --git a/chrome/browser/devtools/protocol/browser_handler.cc b/chrome/browser/devtools/protocol/browser_handler.cc
-index 30bd52d09c3fc..33c7d6d8455fc 100644
+index 30bd52d09c3fc..dd9ef4e3b7cbb 100644
 --- a/chrome/browser/devtools/protocol/browser_handler.cc
 +++ b/chrome/browser/devtools/protocol/browser_handler.cc
-@@ -8,19 +8,32 @@
+@@ -4,23 +4,37 @@
+ 
+ #include "chrome/browser/devtools/protocol/browser_handler.h"
+ 
++#include <algorithm>
+ #include <set>
  #include <vector>
  
  #include "base/functional/bind.h"
@@ -35,7 +40,7 @@ index 30bd52d09c3fc..33c7d6d8455fc 100644
  #include "content/public/browser/browser_task_traits.h"
  #include "content/public/browser/browser_thread.h"
  #include "content/public/browser/devtools_agent_host.h"
-@@ -30,10 +43,21 @@
+@@ -30,10 +44,21 @@
  #include "ui/gfx/image/image.h"
  #include "ui/gfx/image/image_png_rep.h"
  
@@ -57,7 +62,7 @@ index 30bd52d09c3fc..33c7d6d8455fc 100644
  BrowserWindow* GetBrowserWindow(int window_id) {
    BrowserWindow* result = nullptr;
    ForEachCurrentBrowserWindowInterfaceOrderedByActivation(
-@@ -72,17 +96,411 @@ std::unique_ptr<protocol::Browser::Bounds> GetBrowserWindowBounds(
+@@ -72,17 +97,419 @@ std::unique_ptr<protocol::Browser::Bounds> GetBrowserWindowBounds(
        .Build();
  }
  
@@ -437,6 +442,14 @@ index 30bd52d09c3fc..33c7d6d8455fc 100644
 +    out_indices->push_back(found_index);
 +  }
 +
++  if (!(*out_bwi)->GetTabStripModel()->SupportsTabGroups()) {
++    return Response::ServerError("Tab grouping not supported for this window");
++  }
++
++  std::ranges::sort(*out_indices);
++  out_indices->erase(std::ranges::unique(*out_indices).begin(),
++                     out_indices->end());
++
 +  return Response::Success();
 +}
 +
@@ -471,7 +484,7 @@ index 30bd52d09c3fc..33c7d6d8455fc 100644
  
  Response BrowserHandler::GetWindowForTarget(
      std::optional<std::string> target_id,
-@@ -120,6 +538,65 @@ Response BrowserHandler::GetWindowForTarget(
+@@ -120,6 +547,65 @@ Response BrowserHandler::GetWindowForTarget(
    return Response::Success();
  }
  
@@ -537,7 +550,7 @@ index 30bd52d09c3fc..33c7d6d8455fc 100644
  Response BrowserHandler::GetWindowBounds(
      int window_id,
      std::unique_ptr<protocol::Browser::Bounds>* out_bounds) {
-@@ -297,3 +774,910 @@ protocol::Response BrowserHandler::AddPrivacySandboxEnrollmentOverride(
+@@ -297,3 +783,909 @@ protocol::Response BrowserHandler::AddPrivacySandboxEnrollmentOverride(
        net::SchemefulSite(url_to_add));
    return Response::Success();
  }
@@ -1447,4 +1460,3 @@ index 30bd52d09c3fc..33c7d6d8455fc 100644
 +bool BrowserHandler::IsHiddenWindow(int window_id) const {
 +  return hidden_window_ids_.contains(window_id);
 +}
-+

packages/browseros/chromium_patches/chrome/browser/devtools/protocol/devtools_protocol_browsertest.cc

@@ -0,0 +1,123 @@
+diff --git a/chrome/browser/devtools/protocol/devtools_protocol_browsertest.cc b/chrome/browser/devtools/protocol/devtools_protocol_browsertest.cc
+index e57b0883b725f..58bfa8d8f5412 100644
+--- a/chrome/browser/devtools/protocol/devtools_protocol_browsertest.cc
++++ b/chrome/browser/devtools/protocol/devtools_protocol_browsertest.cc
+@@ -20,6 +20,7 @@
+ #include "base/test/test_switches.h"
+ #include "base/test/values_test_util.h"
+ #include "base/threading/thread_restrictions.h"
++#include "base/time/time.h"
+ #include "base/values.h"
+ #include "build/build_config.h"
+ #include "chrome/browser/apps/app_service/app_service_proxy.h"
+@@ -30,6 +31,7 @@
+ #include "chrome/browser/data_saver/data_saver.h"
+ #include "chrome/browser/devtools/devtools_window.h"
+ #include "chrome/browser/devtools/protocol/devtools_protocol_test_support.h"
++#include "chrome/browser/history/history_service_factory.h"
+ #include "chrome/browser/preloading/preloading_prefs.h"
+ #include "chrome/browser/privacy_sandbox/privacy_sandbox_attestations/privacy_sandbox_attestations_mixin.h"
+ #include "chrome/browser/profiles/profile.h"
+@@ -43,6 +45,8 @@
+ #include "components/content_settings/core/browser/cookie_settings.h"
+ #include "components/content_settings/core/common/pref_names.h"
+ #include "components/custom_handlers/protocol_handler_registry.h"
++#include "components/history/core/browser/history_service.h"
++#include "components/history/core/test/history_service_test_util.h"
+ #include "components/infobars/content/content_infobar_manager.h"
+ #include "components/infobars/core/infobar.h"
+ #include "components/infobars/core/infobar_delegate.h"
+@@ -2202,6 +2206,93 @@ IN_PROC_BROWSER_TEST_F(DevToolsProtocolTest,
+   SendCommandSync("Target.getTargets");
+   EXPECT_EQ(2u, result()->FindList("targetInfos")->size());
+ }
++
++IN_PROC_BROWSER_TEST_F(DevToolsProtocolTest,
++                       CreateTabGroupAcceptsUnsortedTabIds) {
++  AttachToBrowserTarget();
++
++  ASSERT_EQ(1, browser()->tab_strip_model()->count());
++
++  base::DictValue params;
++  params.Set("url", "about:blank");
++  params.Set("background", true);
++  ASSERT_TRUE(SendCommandSync("Browser.createTab", params.Clone()));
++  ASSERT_TRUE(SendCommandSync("Browser.createTab", std::move(params)));
++
++  const base::DictValue* tabs_result = SendCommandSync("Browser.getTabs");
++  ASSERT_TRUE(tabs_result);
++  const base::ListValue* tabs = tabs_result->FindList("tabs");
++  ASSERT_TRUE(tabs);
++  ASSERT_EQ(3u, tabs->size());
++
++  std::vector<int> tab_ids;
++  tab_ids.reserve(tabs->size());
++  for (const auto& tab : *tabs) {
++    tab_ids.push_back(*tab.GetDict().FindInt("tabId"));
++  }
++
++  base::ListValue unsorted_tab_ids;
++  unsorted_tab_ids.Append(tab_ids[2]);
++  unsorted_tab_ids.Append(tab_ids[0]);
++
++  base::DictValue create_group_params;
++  create_group_params.Set("tabIds", std::move(unsorted_tab_ids));
++  create_group_params.Set("title", "Unsorted");
++
++  const base::DictValue* create_group_result =
++      SendCommandSync("Browser.createTabGroup", std::move(create_group_params));
++  ASSERT_TRUE(create_group_result);
++  ASSERT_FALSE(error());
++
++  const base::DictValue* group = create_group_result->FindDict("group");
++  ASSERT_TRUE(group);
++  const base::ListValue* grouped_tab_ids = group->FindList("tabIds");
++  ASSERT_TRUE(grouped_tab_ids);
++  ASSERT_EQ(2u, grouped_tab_ids->size());
++  EXPECT_EQ(tab_ids[0], *grouped_tab_ids->front().GetIfInt());
++  EXPECT_EQ(tab_ids[2], *grouped_tab_ids->back().GetIfInt());
++  EXPECT_EQ("Unsorted", *group->FindString("title"));
++}
++
++IN_PROC_BROWSER_TEST_F(DevToolsProtocolTest, HistorySearchUsesVisitTime) {
++  AttachToBrowserTarget();
++
++  history::HistoryService* history_service =
++      HistoryServiceFactory::GetForProfile(browser()->profile(),
++                                           ServiceAccessType::EXPLICIT_ACCESS);
++  ui_test_utils::WaitForHistoryToLoad(history_service);
++
++  const GURL url("https://history-timestamp-test.example/path");
++  const base::Time older_visit = base::Time::Now() - base::Days(2);
++  const base::Time newer_visit = base::Time::Now() - base::Hours(1);
++
++  history_service->AddPage(url, older_visit, history::SOURCE_BROWSED);
++  history_service->AddPage(url, newer_visit, history::SOURCE_BROWSED);
++  history::BlockUntilHistoryProcessesPendingRequests(history_service);
++
++  base::DictValue search_params;
++  search_params.Set("query", "");
++  search_params.Set(
++      "startTime",
++      (older_visit - base::Minutes(1)).InMillisecondsFSinceUnixEpoch());
++  search_params.Set(
++      "endTime",
++      (newer_visit - base::Minutes(1)).InMillisecondsFSinceUnixEpoch());
++
++  const base::DictValue* search_result =
++      SendCommandSync("History.search", std::move(search_params));
++  ASSERT_TRUE(search_result);
++  ASSERT_FALSE(error());
++
++  const base::ListValue* entries = search_result->FindList("entries");
++  ASSERT_TRUE(entries);
++  ASSERT_EQ(1u, entries->size());
++
++  const base::DictValue& entry = entries->front().GetDict();
++  EXPECT_EQ(url.spec(), *entry.FindString("url"));
++  EXPECT_EQ(older_visit.InMillisecondsFSinceUnixEpoch(),
++            *entry.FindDouble("lastVisitTime"));
++}
+ #endif  // !BUILDFLAG(IS_ANDROID)
+ 
+ #if !BUILDFLAG(IS_ANDROID)

packages/browseros/chromium_patches/chrome/browser/devtools/protocol/history_handler.cc

@@ -1,6 +1,6 @@
 diff --git a/chrome/browser/devtools/protocol/history_handler.cc b/chrome/browser/devtools/protocol/history_handler.cc
 new file mode 100644
-index 0000000000000..689f6e900a968
+index 0000000000000..4087a679a527f
 --- /dev/null
 +++ b/chrome/browser/devtools/protocol/history_handler.cc
 @@ -0,0 +1,188 @@
@@ -36,7 +36,7 @@ index 0000000000000..689f6e900a968
 +      .SetId(base::NumberToString(result.id()))
 +      .SetUrl(result.url().spec())
 +      .SetTitle(base::UTF16ToUTF8(result.title()))
-+      .SetLastVisitTime(result.last_visit().InMillisecondsFSinceUnixEpoch())
++      .SetLastVisitTime(result.visit_time().InMillisecondsFSinceUnixEpoch())
 +      .SetVisitCount(result.visit_count())
 +      .SetTypedCount(result.typed_count())
 +      .Build();

packages/browseros/chromium_patches/chrome/browser/extensions/chrome_extension_registrar_delegate.cc

@@ -1,5 +1,5 @@
 diff --git a/chrome/browser/extensions/chrome_extension_registrar_delegate.cc b/chrome/browser/extensions/chrome_extension_registrar_delegate.cc
-index 6eec0585e8925..55c2a73647527 100644
+index adfb4e4d49fa4..409e26fa1cb1b 100644
 --- a/chrome/browser/extensions/chrome_extension_registrar_delegate.cc
 +++ b/chrome/browser/extensions/chrome_extension_registrar_delegate.cc
 @@ -12,6 +12,7 @@
@@ -10,7 +10,26 @@ index 6eec0585e8925..55c2a73647527 100644
  #include "chrome/browser/extensions/component_loader.h"
  #include "chrome/browser/extensions/corrupted_extension_reinstaller.h"
  #include "chrome/browser/extensions/data_deleter.h"
-@@ -317,6 +318,13 @@ bool ChromeExtensionRegistrarDelegate::CanDisableExtension(
+@@ -256,7 +257,17 @@ void ChromeExtensionRegistrarDelegate::PostUninstallExtension(
+     }
+   }
+ 
+-  DataDeleter::StartDeleting(profile_, extension.get(), subtask_done_callback);
++  // Preserve chrome.storage.local data for BrowserOS extensions. These may be
++  // transiently uninstalled during update cycles (e.g., when both bundled CRX
++  // and remote config fail on startup). User configuration must survive.
++  if (browseros::IsBrowserOSExtension(extension->id())) {
++    LOG(INFO) << "browseros: Preserving storage for extension "
++              << extension->id();
++    subtask_done_callback.Run();
++  } else {
++    DataDeleter::StartDeleting(profile_, extension.get(),
++                               subtask_done_callback);
++  }
+ }
+ 
+ void ChromeExtensionRegistrarDelegate::DoLoadExtensionForReload(
+@@ -322,6 +333,13 @@ bool ChromeExtensionRegistrarDelegate::CanDisableExtension(
      return true;
    }
  

packages/browseros/chromium_patches/chrome/install_static/chromium_install_modes.h

@@ -1,8 +1,17 @@
 diff --git a/chrome/install_static/chromium_install_modes.h b/chrome/install_static/chromium_install_modes.h
-index 0cf937413e08a..a61c438a77379 100644
+index ee62888f89705..7ec72d302bc4b 100644
 --- a/chrome/install_static/chromium_install_modes.h
 +++ b/chrome/install_static/chromium_install_modes.h
-@@ -33,48 +33,49 @@ inline constexpr auto kInstallModes = std::to_array<InstallConstants>({
+@@ -21,7 +21,7 @@ inline constexpr wchar_t kCompanyPathName[] = L"";
+ 
+ // The brand-specific product name to be included as a component of the install
+ // and user data directory paths.
+-inline constexpr wchar_t kProductPathName[] = L"Chromium";
++inline constexpr wchar_t kProductPathName[] = L"BrowserOS";
+ 
+ // The brand-specific safe browsing client name.
+ inline constexpr char kSafeBrowsingName[] = "chromium";
+@@ -44,48 +44,49 @@ inline constexpr auto kInstallModes = std::to_array<InstallConstants>({
              L"",  // Empty install_suffix for the primary install mode.
          .logo_suffix = L"",  // No logo suffix for the primary install mode.
          .app_guid =