View Full Version : Flashing your mobo's BIOS (in case of checksum errors etc.)

5th April 2000, 07:04
Flashing the BIOS of your mobo can give strange problems. When you decide to flash your mobo's BIOS, always use a startup floppy like I describe below. Go to points 1), 2) and 3) (skip 2a) !!). See to it that the boot-up procedure in your BIOS is set to A/C/etc.

Boot up your PC with the floppy, and when the flash program asks you if you want to make a backup of your present BIOS, say YES to it, and save that file to the floppy, using a name you can easily remember, like A:/oldbios.txt... the extension to the file doesn't matter that much, as long as you don't use the .exe, .com, .sys or other systemfiles extension.

Now flash your BIOS with your new BIOS file, and when it has done so, exit the flash program, reboot your PC after removing the floppy.

If the flash program tells you that there's a problem with the new BIOS file, then whatever you do, DO NOT POWER DOWN YOUR PC, BEFORE YOU HAVE TRIED TO REFLASH YOUR BIOS, WITH EITHER THE NEW BIOS FILE, OR THE BACKUP OF THE BIOS FILE. (You did make a backup, right?)

So your PC boots up after you thought you flashed your motherboard's BIOS, and it gives you a checksum error?

Or you powered down already, and found out that your PC doesn't start up to what you want http://forums.murc.ws/ubb/frown.gif

Here's an emergency list for you to try.

1) Get a floppy, 1.44Mb ofcourse. Format it on another PC using the /s command in DOS, or format it completely in Windows with the copy system-files checked. Don't use quick-format, as this will usually go wrong!

2) Copy to this disk the (backup) BIOS file, and the flash program.

2a) If you have saved the backed up BIOS file on your harddrive (which is stupid, but who knew?) and you can't reach it, or you have to take out your hdd and hang it in the PC you're using now (too much of a hassle IMO), then goto your mobo's site and download the BIOS file before the faulty one! Save this to the floppy.

3) Make a file on it called autoexec.bat (using either edit in DOS or a text-editor in Windows). In this file you put a link to the BIOS-flasher. (i.e: A:\flashbios.exe) Then save it.

4) Just hope that somewhere in your BIOS you had the option Boot from A/C/etc. set, and boot your PC with this floppy in it's floppy drive.

5) When it will boot up (which I highly doubt), enter the name of the saved BIOS file in the flash program.

5a) When you encounter the checksum error again, you could try to press the Del key (or whatever you need to enter the BIOS) and try resetting it to factory settings.

5b) When you encounter the checksum error again, close down, get your manual out and check if there's a CMOS jumper on the mobo that you can open/close to reset the CMOS. Follow the manual on this procedure, then try to start of at point 4 again. (Beware of static electricity, so earth yourself to any metal piece of your PC casing !!)

6) If you can't find a jumper for the CMOS flush, then power down your PC, remove the CMOS battery (beware of static electricity, so earth yourself to any metal piece of your PC casing !!), power up your PC, power down again and put the CMOS battery back in. Then power up your PC again and go into the BIOS to set your hardware and IRQs again.

Thanks to Long for that last addition to the list.