Atiflash doesnt work with some cards. To see if it does, make a bootdisk with atiflash.exe, atiflash.cfg and dos4gw.exe on it. Boot off the disk and type the following at the prompt:
atiflash -i
If you get a response other than ati adapter not found (or similar) then you are good to go. Your AGP card will be device 0 and it will identify the flashrom.
To back up your bios type:
atiflash -s 0 backup.bin
Now make ANOTHER boot floppy and place backup.bin and atiflash.exe, atiflash.cfg and dos4gw.exe onto it.
rightclick on the autoexec.bat file and select 'edit' (you need to make sure you can see hidden files).
It should look like this:
@echo off
cls
Add the following line to the bottom:
atiflash -f -p 0 backup.bin
Save and exit. You now have a recovery disk in case the flash goes wrong. Just pop it in and boot off it. It will automatically flash back to your original BIOS without you needing to see the screen (BIOS flashes have been known to go bad so that you get nothing on the screen. Just let your PC go through the boot process and give it 1 min or so to access the floppy - make sure all access has finished, rremove floppy and reboot - you will now be OK).
To flash the new BIOS, copy the BIOS you want on to the FIRST floppy you made (I used MUFUS one 97pmufun.bin)
Boot off this disk.
At the command prompt type:
atiflash -f -p 0 97pmufun.bin
Let it flash the BIOS, when all disk activity has ceased, remove disk and reboot.
PLEASE NOTE: the '0' in the atiflash command line is a ZERO (for adapter 0 which is the AGP slot)
Flashing my card helped the memory go from maximum 317mhz to 344mhz so it's definately worth a try.
Good luck