(In reply to matrix8967 from comment #11)
> This is the exact same issue I had and the above solution for removing
> /lib/firmware/amdgpu/raven_dmcu.bin worked for me. 
> 
> For Ubuntu Users on 4.20 you'll need to also run 
> 
> sudo update-initramfs -u
> 
> to update the bootimage. Thanks Chris.

Removing this file and updating my initramfs allows my 2500u HP x360 to
actually boot to the desktop.  Unfortunately, the moment you try to load any
game or even the Steam client, the laptop will hard lock.

The desktop is otherwise functional.