Questions about flashing video card BIOS

[Sean Maxwell]

Would my $400 baby be safe if I flashed it and my other $400 baby to the oldest revision of the BFG BIOS. I do not want to be stuck with a busted 6800 GT without being able to run SLI. The reason I say the oldest, is because i'd guess its the safest. If anyone can tell me otherwise please post.

PS: I cannot overclock my cards and if I turn SLI on I get messed up video. So I need to do something!

Thanks in advance,
Sean