9 To Android 11 Exclusive — Downgrade Oneplus

Step-by-step: Downgrade OnePlus 9 to Android 11 (OxygenOS) — short guide

Warning: This will wipe your device, void warranty, and can brick your phone. Proceed only if you accept the risks.

Before you begin, make sure to:

1. Backup your data: Downgrading will erase all data on your device. Backup your important files, photos, and data to an external storage device or cloud storage service like Google Drive.
2. Charge your device: Ensure your OnePlus 9 is fully charged or at least 50% charged to avoid any interruptions during the process.
3. Install necessary tools: You'll need to install the OnePlus USB driver and the Android Debug Bridge (ADB) tool on your computer.

• Copy downloaded rollback ZIP to phone internal storage (or use adb push).
• Reboot to recovery: adb reboot recovery
• In recovery, choose “Install from internal storage” / “Local upgrade” and select the Android 11 rollback ZIP.
• Confirm and install. Wait until complete.