Hmm. Does it really matter though? I'll give it a try once I get back home.
XFX sent me the original BIOS. its 64KB and file extension .SB
their flash.bat file used the same command as well, atiflash -f -p 0 file.sb
I wonder if it would only take 64KB and by flashing 128KB it killed the ROM chip?
Everything from XFX support is 64KB, but everything saved from atiflash is 128KB?
79x0 BIOS files were originally 128K but the first half of the file was completely empty, hence why most newer BIOS files for the 79x0 cards are only 64K. A lot of manufacturers decided to just throw out the half that wasn't in use. I can almost guarantee your ROM chip is 128K.
By the by, even with the -f tag, WinFlash has aborted operations on me before because the BIOS I was trying to flash was too large for the ROM chip. The chances that you fried your ROM by flashing it with too large a BIOS file are extremely slim.
Something else here is to blame.
As far as file extensions go, I've had WinFlash successfully use .rom, .bin, and .sb files before. The extension you use shouldn't matter as long as the file is actually a valid BIOS file. I can't comment on ATiFlash because it's been years since I've flashed a card from DOS.