Once the installation finishes, your phone will prompt you to . It will boot into recovery mode, perform a factory reset, and then restart into the OxygenOS 11 setup screen. Alternative: The MSM Download Tool
The method to access the Local Upgrade menu varies depending on whether your OnePlus 9 is currently running Android 12 or Android 13. If Your Phone is on Android 12: Open > About Device > Software Update . Tap the Gear Icon in the top right corner. Select Local Upgrade . Tap on the Android 11 rollback zip file you moved earlier. Tap Install Now and confirm the data wipe. If Your Phone is on Android 13:
How to Downgrade OnePlus 9 to Android 11 (OxygenOS 11) – Comprehensive Guide
To downgrade your to Android 11 (OxygenOS 11), you must use a specific rollback package. This process will erase all data on your device , so a full backup is essential before starting. Critical Pre-Downgrade Checklist Backup Data Downgrade Oneplus 9 To Android 11
How to Downgrade Your OnePlus 9 from Android 12/13 to Android 11
General downgrade procedure (high-level) Note: Exact commands and steps depend on the OnePlus build and whether the rollback is “local” (via Settings → System update → local install) or requires fastboot flashing.
Once the installation bar finishes loading, your phone will prompt you to restart. Tap or Reboot . Once the installation finishes, your phone will prompt
Many OnePlus 9 users choose to revert to Android 11 (OxygenOS 11). Newer updates sometimes introduce software bugs, battery drain, or changes to the classic OxygenOS interface. Downgrading restores the original performance, stability, and clean aesthetic that made the phone popular.
| Action | Why It Matters | |--------|----------------| | | Go to Settings → System → System Updates → Disable "Auto-download over Wi-Fi" | | Check for correct baseband | Dial *#*#786#*#* – ensure your IMEI is intact (should be fine with official rollback) | | Reinstall camera app updates | Open Google Play → Update OnePlus Camera – the rollback ships with an older version | | Test critical functions | Wi-Fi, Bluetooth, fingerprint sensor, and alert slider |
Place the ROM file in the of your phone's internal storage (not inside any folders) . Install the downloaded Local Update APK . Initiate the Rollback: Open the newly installed Local Update app . Tap the gear icon in the top right corner . Select your Android 11 rollback file from the list. Confirm the warning that your data will be erased . Finalize and Reboot: Wait for the installation (approx. 10–15 minutes) . If Your Phone is on Android 12: Open
: Since newer OxygenOS versions (12+) often hide the "Local Upgrade" option, you may need to install the OnePlus Local Update Tool . Step 2: Prepare the Package
If official links are down, check the latest community fixes on forums like Reddit or YouTube for mirrored workaround links .
This tool is for emergency use only. It wipes everything and restores the phone to exactly how it left the factory.