Comment # 61 on bug 1177428 from Zbigniew Luszpinski

I confirm. For me after uninstalling and deleting /lib/firmware/amdgpu and
reinstalling official package my system boots normally with the version from
the official repo.

Previously I reinstalled this package few times and done mkinitrd -f but this
not helped so removing /lib/firmware/amdgpu may be crucial before reinstalling
official packageas as I have never done this before Takashi said to do it.

Hint: maybe preinstall script should do cleanup task: rm -rf
/lib/firmware/amdgpu ? This is second time I had to cleanup and reinstall
amdgpu firmware package so problem returns sometimes.