Friday, September 21, 2007

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.

Recovering a Corrupt AWARD BIOS

With AWARD BIOS the process is similar but still a bit different. To recover an AWARD BIOS you will need to create a floppy diskette with a working BIOS file in .BIN format, an AWARD flash utility and an AUTOEXEC.BAT file. AWARD BIOS will not automatically restore the BIOS information to the SYSTEM BLOCK for this reason you will need to add the commands necessary to flash the BIOS in the AUTOEXEC.BAT file.

The system will run the AUTOEXE.BAT file, which will in turn flash the BIOS. This is fairly easy. Here are the steps you need to take.

· Create a bootable floppy diskette
· Copy the BIOS file and flash utility to the diskette
· Create an text file with any standard text editor and add the following lines


In the above example I am assuming that you are using the FLASH763.EXE flash utility. You will need to replace the FLASH763 with the name of whatever flash utility you are using, and replace the BIOSFILE.BIN with the name of the BIOS file you are using.

You will also need to change the ‘/py’ to whatever the command is for your flash utility to automatically program the BIOS without user intervention. If you do not know the command to automatically flash your BIOS type the name of the flash utility with a space and then /? to display the utility’s help
Publish Postscreen.

The help screen should pecify the command switch to automatically flash your BIOS. If you are using the FLASH763.EXE utility then the switch to automatically flash your BIOS is ‘/py’.

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