Like you, I couldn't seem to make any headway with
archive.org.
This is as close as I could get, sweeping the net.
http://drivers.mydrivers.com/drivers/42_17062.htm
http://file2.mydrivers.com/board/bx2000_f8.zip
The file inside there is 256KB and is BX2000P.F8
*******
Have you tried writing to Gigabyte Support, and see
if they can dig up the older one there ? They'll probably
give you some story about "out of support" etc.
The other thing you could look for, is if Gigabyte has
an official forum, and try there for a pointer.
I don't like taking "untraceable" files from the Internet
like the one above. As it's really a crapshoot as to
what is in there. With a hex editor, you could do some
comparisons to your F9 file and see if they're structurally
similar. My favorite hex editor today is HxD.
https://mh-nexus.de/en/hxd/
*******
When loading the F9 BIOS, did you try "load setup defaults" ?
The internal CMOS storage can change from one BIOS revision
to the next, and starting with a fresh clean CMOS RAM content
sometimes helps.
Paul