[Linux ARM64] Workspace dependencies cannot install: missing runtime platform entry and fallback manifest returns HTTP 404

What version of the Codex App are you using (From “About Codex” dialog)?

26.908.40834 (official chatgpt ARM64 Debian package; bundled codex-cli 0.154.0-alpha.6.2)

What subscription do you have?

Pro 20x

What platform is your computer?

Linux 6.17.0-1032-nvidia aarch64 aarch64 Ubuntu 24.04.5 LTS, NVIDIA DGX Spark, native ARM64 installation

What issue are you seeing?

The official ChatGPT desktop app runs on my Ubuntu ARM64 workstation, but the optional Codex workspace dependency bundle cannot install. Settings → Codex dependencies → Diagnose reports that dependencies are not installed. The app's dependency tool returns:

No bundled workspace runtime dependencies are configured yet.

The installation failure occurs while resolving the runtime manifest, before staging or extraction:

2026-09-12T12:06:31.830Z error [primary-runtime-installer]
primary_runtime_bundle_install_outcome
bundleVersion=null
errorMessage="Failed to download primary runtime manifest (404 )."
failureStage=resolve_manifest
outcome=failed
release=latest
target=linux-arm64
trigger=manual_install

This excerpt is reformatted from one log event, with unrelated identifiers omitted.

The latest inspected runtime configuration, selected at 2026-09-12T13:16:42.775Z with source=statsig-layer, contains:

Release	Bundle version	Platform keys
Stable (latest)	26.905.11957	linux-x86_64, macos-aarch64, macos-x86_64, windows-aarch64, windows-x86_64
Alpha (latest-alpha)	26.904.12314	The same five platform keys

Neither map contains linux-aarch64. The selected configuration contains no custom baseUrl.

Inspection of the installed app's resolver shows that native Linux arm64 is correctly normalized to the map key linux-aarch64. With that entry missing, the app falls back to:

https://persistent.oaistatic.com/codex-primary-runtime/latest/linux-arm64/LATEST.json

A separate GET request from the workstation at approximately 2026-09-12T13:32:51Z returned HTTP 404 for this URL. A HEAD request to the configured Linux x64 archive on the same CDN returned HTTP 200. Both curl commands completed successfully at the transport level, without an error message.

After restarting the desktop app, the latest inspected Diagnose event still reports:

2026-09-12T13:16:45.535Z info [install-primary-runtime]
primary_runtime_dependencies_diagnose_finished
bundleVersion=null installed=false problemCount=1

The expected ~/.cache/codex-runtimes/codex-primary-runtime/runtime.json is absent, as is its runtime cache directory. Basic coding operations and local shell commands work; the impact is that workflows expecting the app's bundled Node.js/Python tools and libraries cannot obtain that prepared environment.

What steps can reproduce the bug?

1. Use the official chatgpt ARM64 package version 26.908.40834 on Ubuntu 24.04.5 LTS / NVIDIA DGX Spark. The existing installation was upgraded through the official APT repository; no clean-profile installation was performed.
2. Open the desktop app, select Codex, and open Settings → Codex dependencies.
3. Enable Codex dependencies. On the affected installation, requesting installation fails with the manifest HTTP 404 above. The current settings UI exposes a Reinstall action for requesting a fresh bundle.
4. Select Diagnose. It reports that dependencies are not installed.
5. Inspect the app logs for primary_runtime_bundle_install_outcome, failureStage=resolve_manifest, and target=linux-arm64. The earlier installation attempt logged the HTTP 404; Diagnose itself only checks the installed bundle and does not initiate a new download.

The public fallback URL can also be checked without changing any installation:

curl --silent --show-error --location --max-time 20 \
  --output /dev/null --write-out 'HTTP %{http_code}\n' \
  'https://persistent.oaistatic.com/codex-primary-runtime/latest/linux-arm64/LATEST.json'

Observed on 12 September 2026: HTTP 404.

Control request to the configured Linux x64 archive; this retrieves headers only:

curl --silent --show-error --location --head --max-time 20 \
  --output /dev/null --write-out 'HTTP %{http_code}\n' \
  'https://persistent.oaistatic.com/codex-primary-runtime/26.905.11957/codex-primary-runtime-linux-x64-26.905.11957.tar.xz'

Observed: HTTP 200. The x64 archive was not installed on the ARM64 host.

What is the expected behavior?

For the supported Linux ARM64 desktop preview, enabling the feature should resolve a compatible workspace runtime, install it, and let Diagnose report an installed bundle with a version and no problems.

If this optional bundle is not available on Linux ARM64 yet, the app should clearly report that platform limitation and avoid offering a repair/install loop that ends in a generic missing-dependencies warning and a manifest 404.

Additional information

• features.workspace_dependencies = true in a valid TOML configuration at the latest check.
• The package is the official chatgpt ARM64 package, version 26.908.40834. dpkg --verify chatgpt exits successfully with no differences reported.
• The downloaded chatgpt_arm64.deb is the same version as installed. SHA-256 comparisons of seven selected package files, including the main executable, app.asar, bundled Codex, and launcher, match the downloaded package. The separate workspace runtime is not present in that Debian package's payload.
• The installed desktop executable is native ARM64 and its checked shared-library dependencies resolve. Git 2.43.0, Node.js 24.11.1, and Python 3.12.3 respond successfully. Their presence does not satisfy the app's separate runtime metadata check.
• No relevant custom runtime download override was found in the inspected configuration or launch files. The release configuration has no baseUrl override, and no invalid-runtime-configuration or runtime-configuration-refresh warning was found in the latest session inspected.
• A general standalone Codex CLI was removed during troubleshooting. The desktop app continues to use its unchanged bundled executable. The missing bundle and diagnostic result persist; that separate CLI was not the component fetching this manifest.
• Disabling the optional feature was tried as a workaround, and it is currently enabled again. Disabling it does not install the bundle or make a manual Diagnose check pass.
• There is no new installer event in the latest inspected desktop session; its Diagnose events must not be mistaken for fresh installation attempts. The fresh independent HTTP check above confirms the same fallback URL still returned 404 at the stated time.
• This was investigated on an existing customized profile. No destructive profile reset was performed. The evidence identifies the failing stage and selected release configuration; it does not prove whether a compatible artifact exists at another URL or establish the behavior of every ARM64 installation.

My inference is that the runtime release configuration or fallback download route delivered to this app lacks a usable Linux ARM64 target. Please verify whether the platform entry/artifact needs publishing, the fallback resolver needs correcting, or the feature needs an explicit Linux ARM64 availability gate.

The official Linux documentation lists Ubuntu 24.04 and ARM64 as supported for the desktop preview. My update sequence is the documented one:

sudo apt update
sudo apt install --only-upgrade chatgpt

The payload names no repository files or tests. First inspect the Linux ARM64 runtime target selection, selected release configuration, and fallback manifest URL, then compare them with the published CDN artifacts; done means a supported bundle installs and Diagnose reports a version with no problems, or the UI clearly gates unavailable support.