I dont think you can flash any other bios to a rev 1 card other than a modified original...thats just my thoughts though, no one as far as I know has tried the 7950 bios on either rev 0 or rev 1 7900gs...I would think it would have higher probability of working on rev 1 (just bc I am almost certain it wont work on rev 0) but when you think about it the rev 1 bios was probably implemented strictly so you couldn't flash to higher model gpu's so this wouldnt be wise...Personally I'd try it but I'd most likely settle for copying various sections of each bios, catenating them, and getting nibitor to save the new file but thats just stupid

...In short, I have no real clue on whats going on with 7900's and whatnot since I have a 6800u, but I'd say that your only option is modding a rev 1 bios and flashing it rather than trying to use a different cards bios...