anon626 I think in the video, Side of Burritos does remove the stock key.
anon626 So I basically remove stock key in fast boot mood
Yes
Before flashing the stock factory images, you should boot the device into fastboot mode and make sure the bootloader is unlocked. Then erase the custom Android Verified Boot key to untrust it:
https://grapheneos.org/install/web#replacing-grapheneos-with-the-stock-os
And then just follow the instructions here;
https://flash.android.com/back-to-public
So I think the process would be enable developer options, turn on OEM unlocking, boot into the bootloader, then into fastboot mode, erase the key, then go to the android flash tool and finish flashing stock Android there. If I'm wrong, please someone correct me. :)