Newer OxygenOS versions hide the local installation menu. You must enable Developer Options to reveal it, or install a specific OnePlus legal installation APK if the option remains missing. Unlocking Developer Options Go to . Tap Build Number 7 times consecutively. Enter your lock screen PIN when prompted. Triggering the Downgrade Go back to Settings > System (or System Settings ). Tap System Updates or Software Update .
For many, Android 11-based OxygenOS 11 represents the high point of the OnePlus 9 experience. Users consistently describe the downgrade outcome as “so SPEEDY” compared to the sluggish Android 12 interface. While OnePlus has promised extended security patches for the OnePlus 9 series, getting these security updates often requires staying on newer Android versions — but many users find the performance tradeoffs simply not worth it.
While newer updates introduce novel aesthetics, many power users prefer the inherent to OxygenOS 11. Reverting your phone to this classic system is entirely possible without unlocking your bootloader or rooting your device. Why Users Downgrade to OxygenOS 11 Exclusive
OnePlus provides official rollback packages packaged as .zip files. You must download the specific firmware that matches your phone's regional variant. OnePlus 9 OxygenOS 11 Rollback Package Europe (EU): OnePlus 9 OxygenOS 11 Rollback Package North America (NA): OnePlus 9 OxygenOS 11 Rollback Package downgrade oneplus 9 to android 11 exclusive
After your OnePlus 9 boots into Android 11:
Reports suggest better call quality, specifically regarding VoLTE and VoWiFi stability, on the older firmware. ⚠️ Pre-Rollback Checklist Oneplus 9 Pro | Downgrade to OXYGEN OS 11
When downloaded, your phone or computer may automatically append .jar to the end of the file name. Open your file manager. Locate the downloaded file. Long-press the file and select . Newer OxygenOS versions hide the local installation menu
: Secure your data using cloud services like Google Drive or move files to a computer. Move critical assets including contacts, photos, 2FA tokens like Google Authenticator, and custom app folders.
Navigate to the home screen (this is the "root" directory).
This process will completely wipe your device. Backup all photos, contacts, and documents to a cloud service or external PC. Tap Build Number 7 times consecutively
Before proceeding, you must understand that downgrading is a clean-slate process.
Tap the located in the top right corner. Tap Local Upgrade . Select the Android 11 rollback package from the list. Tap Install Now and confirm the data wipe warning.
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