Review the warning that your data will be deleted, and tap . Step 4: The Flashing Process and First Boot
If you do not disable updates, your OnePlus 9 will immediately download Android 12 or 13 again overnight. Go to > System > System Updates . Tap the Gear Icon in the top right corner. Toggle OFF the "Auto-download over Wi-Fi" option.
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
: Move all photos, contacts, and documents to a PC or cloud storage, as the downgrade performs a mandatory factory reset. downgrade oneplus 9 to android 11 exclusive
This process will completely wipe your device. Backup all photos, contacts, and documents to a cloud service or external PC.
: This process will erase everything on your device, including photos, apps, and settings.
The transition from OxygenOS 11 to later builds marked a massive shift for OnePlus, as the brand integrated its codebase with Oppo's ColorOS. This merger altered the user experience fundamentally. Users frequently downgrade to achieve specific performance goals: Review the warning that your data will be deleted, and tap
While the has seen numerous updates through Android 12, 13, and 14, a growing segment of the community remains loyal to OxygenOS 11 . For many, Android 11 represents the last "true" OnePlus experience before the codebase merger with OPPO's ColorOS.
Before you touch a single file, understand these three non-negotiables:
OxygenOS 12 and 13 remove the native "Local Upgrade" option from the settings menu. You must manually install the official OnePlus system update utility app to flash the file. Download the official OnePlus Local Update APK. Open your file manager and tap the downloaded APK file. Tap the Gear Icon in the top right corner
Here’s a concise, critical review of downgrading the OnePlus 9 (exclusively) to Android 11, based on real-world user experiences and technical considerations.
After you tap confirm, the phone will start installing Android 11.