Successfully flashed an ASUS 7950 DirectCU II TOP
A bit late to the party, but hey we all have our things

Thank you Netkas and Rominator, and others contributing to thread with useful tidbits.
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https://www.techpowerup.com/gpu-specs/asus-hd-7950-directcu-ii-top.b441Card was originally working okay in Mac OS El Capitan 10.11.6 and Windows 10 Pro, with DVI, HDMI and two display ports, but wanted boot screen

Instructions straightforward, and I don't understand all the mistakes people keep repeatedly posting about - read up on terminal usage beforehand. Read your 47 pages and troubleshoot. Take your own ROM, and put into the script.
If it helps other, my script output was as follows:
$ cd into the unzipped bundle folder
$ ./makerom.sh --efifile=7950mac.efi --romfile=efiromheader.rom --originalrom=ASUS7950.rom --devid=679a
running on 7950mac.efi, efiromheader.rom with devid 679a
Patching files 7950mac.efi, efiromheader.rom for device-id 0x679a
Successfully patched efi file
Successfully patched efi rom file
Orig Size = 125440
Comp Size = 47591
47591+0 records in
47591+0 records out
47591 bytes transferred in 0.085020 secs (559764 bytes/sec)
EFI part is ready at 679a.efipart.rom
orig size - 65536
65536+0 records in
65536+0 records out
65536 bytes transferred in 0.119385 secs (548947 bytes/sec)
Before:
OpRom (size=65536, indicator_offset=0x225, indicator=0x80, checksum=0x0)
OpRom (size=48128, indicator_offset=0x31, indicator=0x80, checksum=0x0)
RawData (size=17408)
After:
OpRom (size=65536, indicator_offset=0x225, indicator=0x0, checksum=0x80)
OpRom (size=48128, indicator_offset=0x31, indicator=0x80, checksum=0x47)
RawData (size=17408)
the rom is ready at ASUS7950.rom.efi.rom
I have attached the ROM I flashed for reference.
Sequence was:
1. Took note of switch position on card, it was on position 2 by default. Put card into MacPro and booted into Windows10. Saved this ROM for reference and shutdown and put with in
position 1 to work from. booted into Windows10.
2. Downloaded "amdvbflash_win_3.20.zip", "ati_winflash_2.6.7" and "GPU-Z.2.40.0.exe".
3. Opened GPU-Z and took note of card ID 679a (simple step some people skipped here).
This also verified that the card did not have UEFI as the UEFI box was not checked.
4. Opened amdvbflash, installed driver, and saved the card ROM, placing it on a USB as ASUS7950.rom.
5. Rebooted into MacOS (took a few tries here as Bootcamp installed in unorthodox fashion but got it eventually)
6. Downloaded the "bundle.tar.bz2" from OP, and unzipped
7. Placed original extracted ROM from USB to the above unzipped folder
8. Opened Terminal, and CD'ed into the folder (dragged into Terminal) and pressed return
9. typed '
./makerom.sh --efifile=7950mac.efi --romfile=efiromheader.rom --originalrom=ASUS7950.rom --devid=679a' and pressed return
10. ROM to flash appeared in folder, and put onto USB drive
11. Rebooted into Windows 10
12. From USB, placed ASUS7950.rom.efi.rom onto desktop
13. Opened up amdvbflash_win_3.20, and loaded the ASUS7950.rom.efi.rom and flashed
14. Tested by opening up GPU-Z. and checking that UEFI box was checked. Confirmed.
15. Removed installed driver for amdvbflash_win_3.20 - some security issue
16. Reboot into Mac, and voila BOOTSCREEN! Checked in System profiler and card name explicitly. Tested card with full insane detailed resolution win XPLANE 9 and 10. Amazing
Thank you again!
P.S. Had a 6Pin Mini PCIe to 6Pin GPU power cable but had to make another one from cables and connectors I had. A good reference table and pic attached
