to (OxygenOS 11), you must use a specific Rollback Package . ⚠️ Critical Warnings
As of 2025, Android 11 is technically outdated. You will miss out on security patches newer than February 2024 (depending on your final build). However, for many, the and performance of Android 11 on the OnePlus 9 outweigh the theoretical security risks—especially if you avoid downloading suspicious APKs.
While the official rollback method usually utilizes a local upgrade APK file, keeping your device accessible via developer tools is a smart safety measure. Navigate to . Downgrade Oneplus 9 To Android 11
Your phone will take longer than usual to boot up for the first time. Once it boots into Android 11, you will see the classic OxygenOS setup wizard.
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. to (OxygenOS 11), you must use a specific Rollback Package
Tap on , select Format Data , and confirm the action.
You must know your phone's exact model number (e.g., LE2113, LE2115, LE2117) and your region (e.g., India (IN), Europe (EU), North America (NA)). The easiest way to find this is to go to Settings > About Phone . Downloading and using firmware from the wrong region for your device can cause serious issues. However, for many, the and performance of Android
Tap or Upgrade . The phone will reboot into recovery mode and begin installing Android 11.