The work is fairly easy, only 5 bytes need to be changed. So, we apply the 'part number fix', change it to 113-4E353BU-O4E

He sent me the original dumped ROM, I open it, and obviously the part number is not the one that same as the Apple developer kit. So, I worked with him to correctly fix the card. Therefore, everyone can benefit from the discussion. I prefer to discuss at here rather than PM. Of course, please feel free to post any questions (or share your work) at here. Then start everything from the beginning again. If this happened, I suggest you also flash the MASTER BACKUP ROM image back to the card. Even you did something wrong, the card should still work, but just still shows R9 XXX in High Sierra. If you only edit the part number, some useless info, or that large piece of FF. So, as long as the software take it, the ROM should be OK. I am not 100% sure, but from memory, if the checksum is wrong, it should refuse to flash the ROM onto the card. I didn't use the ATIWinFlash for a while already. Then dump it out again to double check if it's the same as the MASTER BACKUP (You may simply check the modded bytes by yourself, or use some software to compare them automatically). If there is ANY error during / after flash, do NOT restart, but flash your MASTER BACKUP ORIGINAL ROM image back in. And if anyone want to try this 'part number fix' on the new Sapphire PULSE RX580 8GB card, please AVOID the Polaris BIOS Editor. Thanks Teddy for providing his card, ROM, and time for me to test the 'fix'. Before you do anything to the ROM image, backup your original dumped ROM at least twice, and only edit the copy of copy, NEVER edit the original ROM image backup. GPU-Z can also be used to dump the ROM), I open it (with HexMiner, but any hex editor can do the job), and obviously the part number is not the one that same as the Apple developer kit. He sent me the original dumped ROM (by using ATIWinFlash in Windows. You can do that in a PC, or Bootcamp Windows on the Mac Pro (and NO, this cannot be done within Parallel Windows, or any virtual machine).

So, the following procedures are all base on Windows. I am quite sure the whole process can also be done in DOS or Linux, but I don't know how to do it.

No need to boot back to MacOS until everything is done. In fact, the whole process can be done within Windows. I use macOS calculator and Hexminer (Mac apps) to assist him because I work with him via the internet, and I am in MacOS. More than one users reported that, the card 'fixed' in this way will only shows back screen once driver is loaded (in Windows), or all the way black screen (in MacOS). Which may eventually apply the fix on an important byte and causing error. Despite the PULSE ROM size is just 256k, it seems the Polaris BIOS Editor may still base on the 512k size assumption to apply the checksum fix.

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