You could try this, 50/50 chance, no returns
AMIBIOS Recovery bootblock:
1. Copy a known working BIOS image for your board to a floppy and rename it to AMIBOOT.ROM.
2. Insert the floppy in your system's floppydrive.
3. Power on the system while holding CTRL+Home keys. Release the keys when you hear a beep and/or see the floppy light coming on.
4 . Just wait until you hear 4 beeps. When 4 beeps are heard the reprogramming of the System Block BIOS went succesfull, so then you may restart your system.
Some alternative keys that can be used to force BIOS update (only the System Block will be updated so it's quite safe):
CTRL+Home= restore missing code into system block and clear CMOS when programming went ok.
CTRL+Page Up= restore missing code into system block and clear CMOS or DMI when programming went ok.
CTRL+Page Down= restore missing code into system block and do not clear CMOS and DMI area when programming went ok
Btw: the alternative keys work only with AMIBIOS 7 or higher (so for example an AMI 6.26 BIOS can be only recovered by using CTRL+Home keys).
Boot Block Recovery for FREE
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BLACKOUT Flashing
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Recovering a Corrupt AMI BIOS chip
With motherboards that use BOOT BLOCK BIOS it is possible to recover a corrupted BIOS because the BOOT BLOCK section of the BIOS, which is responsible for booting the computer remains unmodified. When an AMI BIOS becomes corrupt the system will appear to start, but nothing will appear on the screen, the floppy drive light will come on and the system will access the floppy drive repeatedly. If your motherboard has an ISA slot and you have an old ISA video card lying around, put the ISA video card in your system and connect the monitor. The BOOT BLOCK section of the BIOS only supports ISA video cards, so if you do not have an ISA video card or your motherboard does not have ISA slots, you will have to restore your BIOS blind, with no monitor to show you what’s going on.
AMI has integrated a recovery routine into the BOOT BLOCK of the BIOS, which in the event the BIOS becomes corrupt can be used to restore the BIOS to a working state. The routine is called when the SYSTEM BLOCK of the BIOS is empty. The restore routine will access the floppy drive looking for a BIOS file names AMIBOOT.ROM, this is why the floppy drive light comes on and the drive spins. If the file is found it is loaded into the SYSTEM BLOCK of the BIOS to replace the missing information. To restore your BIOS simply copy a working BIOS file to a floppy diskette and rename it AMIBOOT.ROM, then insert it into the computer while the power is on. The diskette does not need to be bootable or contain a flash utility. After about four minutes the system will beep four times. Remove the floppy diskette from the drive and reboot the computer. The BIOS should now be restored.