BlossomOS uses atomic updates - the entire system image is replaced at once, as a single operation. Either the update fully applies and the system reboots into the new version, or nothing changes at all. There’s no halfway state where a partial update breaks your system.

How Updates Work

BlossomOS is built on Fedora Kinoite, which uses rpm-ostree to manage the base system as a versioned, immutable image. When an update is available:

1. The new system image downloads in the background
2. You get a notification that a reboot will apply the update
3. On reboot, the system switches to the new image in seconds
4. If something goes wrong, you can boot back into the previous version

Your personal files, settings, and installed apps are unaffected by system updates.

Updating Through Arc

Arc shows system updates alongside app updates. Open Arc Store and go to Updates. System updates appear with a reboot indicator. Click Update to download and stage it, then reboot when convenient.

App Updates vs. System Updates

Rolling Back

If an update causes a problem, you can boot into the previous system version:

1. Reboot your machine
2. At the GRUB boot screen, select the previous BlossomOS entry (the one without “current”)
3. BlossomOS boots into the last working version

To make the rollback permanent (so the old version is the default on next boot):

rpm-ostree rollback

Run this in a terminal, then reboot. The system goes back to the previous deployment and the failed update is removed.

Checking Update Status

rpm-ostree status

This shows all installed deployments, which one you’re currently running, and whether an update is staged for next boot.

Pinning a Deployment

If you want to keep a specific version available even after future updates, you can pin it:

rpm-ostree pin 0    # pin the currently booted deployment

Pinned deployments are never automatically removed. Unpin with rpm-ostree pin --unpin 0.

Automatic Updates

BlossomOS checks for updates automatically and downloads them in the background. By default, it does not reboot automatically - you choose when to apply them. You can configure this behaviour in System Settings → System Updates.

System Base is Read-Only

The /usr directory and most of the system are read-only by default. This is intentional - it prevents software from modifying system files in ways that could break things or introduce security issues.

If you need to temporarily write to /usr for testing (not recommended for production use):

rpm-ostree usroverlay

This creates a temporary writable overlay that reverts completely on the next reboot. Available in Arc Store as a one-click option under CLI tools.