- Goto https://steamdeck-images.steamos.cloud/steamdeck/ and get the version you want
The full URL will be the .raucb file, i.e. https://steamdeck-images.steamos.cloud/steamdeck/20250929.1/steamdeck-20250929.1-3.7.16.raucb
- Run command
sudo steamos-atomupd-client --update-from-url [URL]