[OnePlus 9RT] Templars69_:
Hi everyone,

After a few days of struggling, I can share with you my recent experience in case it can benefit someone.

I received a OnePlus 9RT from China mainland (MT2110) loaded with ColorOS11, I wanted to switch to OxygenOS to benefit Google Apps and remove various chinese bloatware.

I installed lastest adb (Version 33.0.2-8557947) and fastboot (version 33.0.2-8557947), add to PATH under environment variables.

After allowing the developer mode, ticking OEM unlock and USB debugging, it was impossible for adb to recognize the device with Media Transfer Protocol (MTP), and I had to go from Picture Transfer Protocol (PTP).

Once the device recognized in adb and fastboot, I tried to access bootloader mode in the following two ways:

- Press simultaneously volume up, down and power -> Nothing Happened

- Run adb reboot bootloader -> It quickly flashed the bootloader logo and proceed to normal boot

I contacted the OP customer service in China and tell them I could only access Recovery, Fastbootd mode but not the bootloader mode. Being under the 7 days no questions asked policy, they send me a new One Plus 9RT today.

This time, keeping the same Windows configuration, adb and fastboot version, I was able to unlock the bootloader, flash OxygenOS11, and relock the bootloader without any issue. Shoutout to the team, amazing job!

Summary of the steps I followed:

1. Download adb (Version 33.0.2-8557947) and fastboot (version 33.0.2-8557947) from XDA forum

2. Disable Driver Signature Enforcement on Windows 10 (Shift + Reboot Windows / Advanced Boot Options / Disable Driver Signature Enforcement)

3. Download Fastboot ROM OxygenOS A.11.zip from XDA forum and extract the zip

4. Check adb

> On the phone: Enable developer mode, Allow USB debugging, Allow OEM unlock

> On Windows 10 (allow always authorized device):

Your device should show here identified by the device code

5. Check fastbootd

Wait for the phone to reboot in fastbootd mode

Your device should show here identified by the device code

Warning: If the device don't show up, go to Device Manager on Windows, click "Modification on hardware", add drivers manually, load fastboot driver

6. Check bootloader

Wait for the phone to reboot in bootloader mode

Your device should show here identified by the device code.

7. Unlock bootloader

From the bootloader mode type

Your device should show here identified by the device code

Access the unlocking process on the phone, using volume arrow to move and power to select.

Let the phone reboot. Reboot in bootloader mode, your bootloader should be unlocked.

8. Install OxygenOS11

Set your phone in bootloader mode

Wait for the phone to reboot in bootloader mode

Open CLI (command line interface) from the folder extracted in step 3: Open the folder and type cmd in the navigation bar.

Check fastboot status

If device shows up type

WARNING: DOT NOT UNPLUG THE CABLE DURING THAT STEP NOR TURN OF YOUR COMPUTER

Wait for the Fastboot ROM installer to complete (between 5 and 7 minutes)

9. Lock the bootloader

On the phone: Enable developer mode, Allow USB debugging, Allow OEM unlock

Your device should show here identified by the device code

Let you device boot, you can check in bootloader mode that your bootloder has been locked successfully.

That was my experience, hope it helps :coffee: