Comment # 7 on bug 108585 from Joel

(In reply to Benjamin Herrenschmidt from comment #6)
> Dan... did you do some firmware changes here ? Could it have to do with the
> versions differences between petitboot and the final kernel ?

FWIW, Talos II machines use a fork of op-build that include the amdgpu driver
in petitboot. (They also appear to be stuck on 4.16).

I was experimenting with the same.