Still, AMD is releasing new bioses for the 5600, they raised frequencies and TDP allowance after Nvidia cut the RTX 2060 prices. This means the Navis can be BIOS flashed. Modified bioses is another issue.
Of course they can...even before 5600, you could flash 5700 with 5700XT bios...but all of those are AMD-made, already signed
bios-es. Flashing is not a problem, but signing