so just an update on this,
This particular card, a Sapphire 7950 dual x boost, uses a modified reference bios. None of the reference bios for the 7950 will patch. So any reference designed 7950 is out of luck.
I've gone through a very large list of 7950 bioses from every manufacturer as well. The only progress i was able to make was one Gigabyte bioses that patched and flashed, but had a BSOD for ATIMDAG.sys when windows 7 loaded drivers. I could see the lowered resolution start screen though before it crashed. I tried uninstalling/installing different sets of drivers but no luck. Other bioses either won't flash or won't post.
Also, I was able to successfully patch and flash an RX480, not sure if anyone's attempted that before but it lacks analog outputs, so not really helpful for CRT use.
I may pick this up when I have more time. Going back to that Gigabyte bios and trying different drivers