downgrading-oneplus9-oxygenos.md 1.8 KB
Downgrading Oneplus 9 Oxygen OS
After unbricking a Oneplus 9 device, I expected the jump from Android 11 to Android 12 to have some sort of warning - but it jumped straight to Android 13.
As there is no Lineage compatible version for Android 13 at the time of writing, this was too much of an upgrade.
Note that downgrading this way wipes the system, so back up anything important
Download the old system update APK from Oneplus and put it in the phone's download folder: https://oxygenos.oneplus.net/OPLocalUpdate_For_Android13.apk and install
This is required, otherwise you need to do it via fastboot, the same as the unbrick method
- Native system update app does not allow downgrading
- If not already allowed, you'll be prompt to allow the File Manager permission to install 'unknown' apps.
Download the rollback package from Oneplus, this article has links to rollback variants (North America, India, Europe) coming directly from Oneplus
- Put the zip in the device root, not Download/update or anything like that. The system update APK specifically looks in the system root for the rollback zip.
- Rollback packages to Open beta / forum thread for Android 12 to Android 11
Reboot when prompted
- After the 1+ / Android splash screen, there was a brief screen where Chinese text with a progress bar shown, it lasted for about 30 seconds and booted into the Oxygen OS splash screen
- Unclear on what it said, but considering the package is sourced from Chinese manufacturer Oneplus, likely just a diagnostic message
Locate Build mode in Settings and tap 3-4 times to get developer mode back