I believe you can do that, if you did the bios correctly and didnt loose power while doing bios, i was told you can do that. The program I have has me do something like "a:\flashbios -p 0 rom.rom" which the 0 is the agp slot so you should be able to boot back and check it out and save your video. I hope you made a backup of your original video card bios

. If you need any help with programs or how to do stuff even bios files let me know I can help you. I flash my 9600 XT many times now for testing and such and its really hard to find a newer solution for the card. I can't even really overclock this card without getting stutters but it is cool how to be able to flash cards. I wish I could find an updated bios version though for the 9600 XT.
Sorry its been a year, i just joined the forums 10 minutes ago, you probably don't have the card anymore.