Actually the EFI Boot loader boots in legacy mode on older mainboards such as ASUS P8H61M-LX R2.0 and it doesn’t boot on legacy mode on AMD RYZEN AM4 mainboards it hangs completely.
Why am i talking about this?
Because the radeon_hd driver doesn’t work when i boot in EFI mode only work correctly in legacy mode so i can’t test it on modern ryzen boards (for example for test if RX580 works oob with radeon_hd [i think it’s the case] and the boot manager has some problems booting on legacy mode as a safe option instead of booting on UEFI mode).