That kind of bios is not exist for non ref cards. Each brand , each model number need a different modded bios . If you going to flash a Asus Bios to your XFX card , you going to brick you Card.
I didn't know It would required one for each manufacturer.
Thanks for all the info.
I have different brands of RX 480 total of 3 of them(XFX, Saphire) , and use only one bios, they are behaving correctly. I have them setup in one rig, but have to set the fans manually @80% to have them behave correctly. Only branch I used different' is RX 480 Nitro. I never tried using the the 30Mh Low power bios.
Are they all reference RX 480? If so, you can use the same BIOS as the only difference in the BIOS is the manufacturer's ID.