• Welcome to TechPowerUp Forums, Guest! Please check out our forum guidelines for info related to our community.

Help with creating Apple HD5770 Hybrid ROM


New Member
May 26, 2012
2 (0.00/day)
Hi everyone!

I've been a long time visitor to these forums, but now I need your help!

Here is a quick run down:

I have two reference Apple AMD/ATI HD 5770's (x2 mini display x1DVI ports) that I wish to run in Crossfire in my Mac Pro under Windows 7 x64. Now like many other people who have tried to CF these very cards, they have found that the 10.11 drivers are the last drivers to work with these cards in a CF configuration. These however are verrry old drivers, newer drivers throw up a atikmdag.sys BSOD when you enable CF.

Having tested the two cards on a normal PC with a CF enabled motherboard, I have found that the latest 12.xx drivers still do not work with crossfire. Which narrows it down to the cards.

I have flashed both cards with the standard PC 5770 reference ROM but the monitor ports are mapped incorrectly, and the EFI module of the ROM is missing preventing OSX booting. On a Windows machine with a compatible motherboard with the cards flashed, I can indeed enable Crossfire without a BSOD which means that this is a Apple ROM issue.

So what am I trying to do?

What I would like to know is; is it possible to take the standard PC HD5770 BIOS and merge it with the Apple EFI module of the Apple BIOS and correct the monitor port mapping so that it is configured the same as the origional Apple BIOS.

Basically I wish to:

  • Use the PC BIOS to enable Crossfire with the newer drivers.
  • Keep the EFI module of the orgional Apple BIOS to allow me to view the EFI bootloader on the Mac.
  • Map the correct monitor ports on the PC ROM using the routing from the Apple ROM.

I have run through both the Apple and the PC ROMs with a hex editor but as my understanding of Hex is limited, I am having a hard time. If anyone has some knowledge of BIOS's that may be able to help me create a hybrid ROM or knows of a tool I can use to extract the code I need I would greatly appreciate the assistance!

Thanks in advance!

**I have attached both ROMs in case someone with knowledge would like to take a peek at them.**



New Member
Feb 5, 2013
1 (0.00/day)
Did you ever get this worked out?

I recently got two of these cards, and would love to use them in my PC in xfire, Did you ever get his to work?