Yes. Exclusive feedback from our testing lab (OnePlus 9, 8GB/128GB, originally on Android 13):
You lose security patches (Android 11’s last security update was February 2023) and newer privacy indicators, but for performance enthusiasts, it is a no-brainer.
# List current logical volumes
fastboot getvar all
If Android 11 becomes unstable, revert using MSM Tool (not fastboot). Download the correct ops file for your model. MSM bypasses all partition locks by rewriting at the Qualcomm Sahara protocol level.
How to Downgrade Your OnePlus 9 to Android 11 While newer software often brings exciting features, many users find that the original OxygenOS 11 (Android 11) provides a smoother, more classic experience on the OnePlus 9 series. This guide explains how to safely roll back your device. Pre-Installation Checklist downgrade oneplus 9 to android 11 exclusive
Before starting, ensure you have taken the following precautions:
Backup Your Data: This process will erase everything on your device, including photos, apps, and settings.
Battery Level: Keep your phone charged to at least 50% to avoid a mid-process shutdown. You lose security patches (Android 11’s last security
Check Your Region: Downgrade packages are region-specific (India, North America, or Europe). Using the wrong one can lead to compatibility issues. Step-by-Step Downgrade Guide 1. Download Necessary Files
You need two specific files: the Rollback Firmware Package and the OnePlus Local Update APK.
Rollback Package: Download the stable Android 11 zip for your region from the OnePlus Community forums. Downgrading is not without its casualties
Local Update APK: Since modern OxygenOS versions hide the local upgrade option, you must install the OPLocalUpdate APK to perform the installation. 2. Prepare the Files
Rename Extensions: Sometimes downloads append extra characters (like .jar or .zip.j). If the firmware ends in .jar, rename it to end exactly in .zip. If the APK ends in .zip, rename it to .apk.
Move to Root Directory: Transfer the firmware package directly into your phone’s internal storage (outside of any folders) so the update tool can find it. 3. Flash OxygenOS 11 [CLOSED] Roll back - OnePlus Community
Downgrading is not without its casualties.
| Feature | Status on Android 11 |
|--------|----------------------|
| Material You theming | ❌ Not available |
| Private Safe (in Files) | ❌ Limited version |
| Work-Life Balance 2.0 | ❌ Only v1 |
| Always-on Display customization | ❌ Basic |
| Security patches | ❌ Stopped after early 2022 |
| Some GCam mods | ✅ Better support |