Brick Saved!! OnePlus 8 Pro Oxygen OS 12 to Android 11 downgrade brick saved. Methods I used and pitfalls.

[camwang]

Background:​

• OnePlus 8 Pro IN2020
• Original OS version is OxygenOS 12 Android 12

How my phone turned into brick:​

• Try flashboot unsupported TWRP and other third party recoveries.
• After a few tries, eventually causing my phone turning into a brick

What my error looks like:​

• Not able to boot into system
• Showing "the current image(boot/recovery) have been destroyed"
• Can access fastboot and detect by system

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Method:​

• Follow the steps in How to UNBRICK OnePlus 8 or 8 Pro! by Max Lee (Thank you my man, Max, for this video)

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Pitfalls in 2022 (IMPORTANT before UNBRICK!):​

A USB 2.0 and Third-party USB cable are highly recommended​

I was unable to boot into Quadcomm EDL mode while using the stock cable and USB 3.0 connector. Pressing the correct Volumn Up & Volumn Down and Power Button will boot the phone to fastboot in no time.
I successfully got into the EDL mode and finished flashing the phone using my iPad Pro Type-C charging cable which is an USB 2.0 one.

Use a newer version of the Qualcomm driver if you find the device not correctly detected​

Use Qualcomm HS-USB QDLoader 9008 driver.
A new Quadcomm driver will help you flash your device correctly the first time!!!

Windows 11 won't let you install unsigned driver by default, but there's a way round​

1. Press Shift key while click Reboot in start menu to enter Advanced Options
2. Click Trouble shoot in Advanced Options
3. Click Advanced options, click Startup Settings then click Restart
4. After restart press 7 when required
5. If your computer won't restart, just unplug your phone temporarily

after this your device will detect by your computer correctly.

Pressing buttons requires special timing and preconditions and a few more tries​

• To fully power off your phone, press Volume up and Power button for 10 seconds. Release immediately after the screen turns black.
• Your phone is in the state of powered off even your screen displaying error message or charging animation, just make sure it's not in fastboot, recovery or booting animations.
• Connect your phone to your computer before press Volume up and down and Power Button all at the same time to enter EDL mode.
• Prepare yourself with Device Manager and MSM tool open and configured correctly before your phone enter EDL mode. There's a about 10 second window for you to start flashing.

Fail amid your MSM flash process:​

Don't panic if you see error message saying you didn't finish flashing​

• You can flash it anytime just make sure checking all the things above and enter EDL mode

Check these things：​

• Check your Windows can install the unsigned driver correctly
• Check Device Manger in Control Panel if your device is correctly detected as a COM device as Qualcomm HS-USB QDLoader 9008 or something like this
• Use administrator privilege to open the MSM software
• Check your cable connection is stable or not.

Finally, thanks Dr.E (Max Lee) for your help. Without your video instructions, I won't revive my phone. It spares my pain to ask my dad for money for a new phone I don't actually need.

Hope everyone could find some helpful information in this post and flash your phone like a champ.

 

[camwang]

A even better way to enter EDL mode is power off and unplug your device, and after hold volume up and down at the same time, plug in the USB 2.0 cable to the computer. It works every time!!