[coreboot] AMD Chromebooks with upstream coreboot: non-working iGPU

[Paul Menzel]

Dear coreboot folks,

In #[e-mail] there is a report, that self-built coreboot 
won’t work on AMD Chromebooks. The problem seems to be that you need a 
verstage signed by Google/AMD. Otherwise the GPU driver breaks.

Is that expected/known? If not, does somebody have instructions how to 
build a coreboot image from upstream coreboot.

Kind regards,

Paul