Were there any errors in the ADB windows during flash? That'd be step one
Nope, just a regular OnePlus 8
Okay so I do have some errors, specifically:
Yes I swapped the versions fixed now
ROM flashing has been fixed in latest build. All A11 ROMs can flash fine. A12 is iffyI'm not sure about that, but TWRP for OnePlus 8 is still in progress and have issues with Android 11-based ROMs support let alone with Android 12 ROMs support, I recommend you to sideload (how author mentioned) by LineageOS recovery (https://forum.xda-developers.com/t/rom-12-0-evolution-x-12-22-2021-unofficial.4368233/post-86140051)
If sideloading Magisk isn't working, just use the manual boot.img patcher method.I decided to do a fresh install; however, I too have lost root as Magisk asks me to patch a file...odd. I did try the following methods:
1. Sideload ROM, factory reset etc, boot phone then sideload magisk canary.zip boot phone...no root.
2. Sideload ROM, then sideload magisk canary.zip straight after then factory reset et al, boot phone....no root.
After trying to sideload magisk canary.zip, i get the following error in recovery
E: footer is wrong
Update package verification toom 0.2s (result 1)
E: Signature verification failed
E: Error: 21
Install from ADB completed with status 2
installation aborted .
Just curious, i did install arrow recovery, but whilst in recovery, the top left of the screen it says android recovery.
Any help is greatly appreciated.
Same process. Download the latest Magisk Canary build and rename it to .zip. Flash in recovery with adb sideload.