Ryzen, Vega8

Kernel 5.7.11
when amdgpu diabled in BIOS (external GPU set as main) Kernel crash on firt secon of loading...

Kernel 5.6.14
boot without problem, just message "amdgpu:Fatal error during initialization" at first 5 messages of kernel loading

Kernel parameter
amdgpu.dc=0 has no effect