i hate to ressurrect topic but
maybe it will help fellow googlers
https://www.techpowerup.com/download/ati-atiflash/techpowerups UEFI Shell Version allowed me to flash bricked card.
in windows version no matter what i did, "error reading from ROM" was the message.
i can't recall the exact syntax
amdvbflash -p 0 romname.rom
if i recall correctly.
UEFI Shell version, is the normal version and won´t work for all bricked cards. The only trick, which is working on every AMD card is this one:
Still cannot POST!!!
Even after you used one of the methods above and still cannot POST, your bricked card is probably preventing the system from working. In this case, you'll have to locate the video BIOS chip and short 1-8 pins with a paperclip, or small wire, or by soldering until flashing is complete. The BIOS chip is usually 8-pin and located on the rear, bottom side, tagged as U1-12 on the PCB, but be sure to verify first by searching online the text written on the chip (e.g. A25L0100). Search engine results should be related to "flash memory chip", not a regulator or anything else.
link:
https://www.techpowerup.com/forums/threads/how-to-recover-from-a-bad-video-bios-flash.265939/