Oh yea sorry. I didnt reistall OxygenOS. I thought it could be recoverd with twrp.
I tryed following this guid just with the Oneplus 6 version.
([HOWTO] OnePlus 6T: Roll-back to stock OxygenOS ROM after a brick / being stuck in a loop)
Is this the right way? Since iam not sure becasue im pretty pretty new to this whole phone tinkering and got an error while doing the first line “fastboot flash aop_a images/aop.img”
Error:
$ fastboot flash aop_a images/aop.img
Sending ‘aop_a’ (180 KB) OKAY [ 0.016s]
Writing ‘aop_a’ FAILED (remote: 'Flashing is not allowed for Critical Partitions
')
fastboot: error: Command failed
The device state in the bootloader is currently unlocked.