dump bios from your 77xx-79xx card and save it into this folder as cardname.rom find your 4 digit deviceid (if its 697a1002, then obviously you need only 697a, since 1002 is ATI vendor id (dont be stupid here, please)) run script, replace 697a with your deviceid and cadname.rom with your actual original video bios file
./makerom.sh --efifile=7950mac.efi --romfile=efiromheader.rom --originalrom=cardname.rom --devid=697a
WARNING, if you have uefi part in bios already (e.g. if its much larger than 65kb) then it will be overwritten with new efi part ORIGINAL ROM CREATOR 7xxx Efi Test