Computer Technicians 202: BIOS Functions and Firmware Flashing

Indecent exposure

As we explained above, most modern BIOSes are stored on flash ROMs. They’re manufactured reprogrammable for very simple reasons – expandability and ease of patching. Like all pieces of software, BIOSes may not be infallible. Sometimes a mistyped instruction might be overlooked, or the BIOS may clash with a component, usually the RAM or CPU and might fail to utilize it properly. For instance, a BIOS designed to run on a computer with a 333MHz bus won’t be able to address more than 256MB of DDR400 RAM, or it might not let a CPU run at its proper clock, usually tuning it down. In cases like these, a BIOS flash might be able to alleviate the trouble.
The first step in flashing is to determine whether or not you actually need a flashed BIOS. Maybe the current revision of the BIOS doesn’t fix your problem, if it is, indeed, the BIOS’ fault. The second step is obtaining the proper revision of the BIOS for your motherboard – it’s written out in bold, so it has to be important, right? It’s absolutely critical that you download the BIOS exactly for your motherboard model. If there are two very similar motherboard models, double-check which one you have, either by looking at the motherboard invoice or by using a tool such as Everest Home. Sometimes, the BIOS will function on both, but it’s best to be sure – double-check and then download. Finally, write down all of your BIOS settings, no matter how many pages of a notebook you have to spend on it. You’ll thank yourself later.
While the new BIOS file (usually under a megabyte in size) is downloading, take the time to check the motherboard manufacturer’s documents on how to perform the flashing itself. Sometimes, you can utilize an in-OS updater which can integrate the new BIOS seamlessly from the operating system, eliminating complications – consequently, most of them also have automatic checkers that back up the old BIOS in case of failure, and verify that you’re indeed updating with the right BIOS. However, it’s better to rely on common sense and just have the correct BIOS down. On the other hand, you might be stuck with a DOS-based flash updater, in which case you’ll require an clean bootable floppy (under the Driver Free Disk section), an empty (preferably rewritable) CD medium or a USB stick, if your system supports either of those. Once you’ve copied the files to the floppy, restarted the machine, set it to boot from Floppy/CDROM/USB first, and restarted again, you’ll have to use the instruction provided by the BIOS manufacturer to reflash the BIOS. The process is relatively painless and usually takes under a minute, unless…

Occupational hazards

In case you didn’t get the hint just yet, BIOS flashing is very, very risky. The first hazard we’ve already mentioned – flashing your BIOS with the version intended for the wrong model. While you might just be able to get the system barely operational enough to reflash it with the right version, chances are that’s not going to happen. If you were wise enough to purchase a motherboard with the dual BIOS chips, the machine will automatically discard the new, flashed version, and boot from the old one. On the other hand, if you’re stuck with a single-chip BIOS, you’re pretty much dead in your tracks. Some motherboards have BIOS chips that can be simply popped out of their sockets, while others have them soldered to the circuit board – either way, start looking for local electronics repairmen with BIOS reprogrammers. These boxes allow you to reflash the BIOS externally, while it’s not connected to the PC, thus letting you reflash it over and over if trouble arises. Soldered BIOSes are particularly nasty, as they have to be desoldered very carefully, again, best left to pros.

Despite the risks of flashing the BIOSes the wrong way, by far the biggest threat to a successful BIOS flash is power failure. Absolutely nothing can quite ruin a day like a power outage during BIOS flashing. In case the BIOS is still in the “dumping” (backup) phase, you’re relatively safe, however, if the flashing process was stopped in its tracks, you’re left in the same situation as if you’d flashed it the wrong way – with the added hazards power outages, brownouts or power spikes bring. If you suffer a power spike, and BIOS only needs a reflash, without anything burning out, you can count yourself extremely lucky – and foolish if you attempted reflashing in the middle of a storm. BIOS flashes are like kites, best done on sunny days.

Note: If a BIOS flash went bad our how to recover from a bad BIOS flash may help you.

The aftermath of burning

Provided you avoided both the common pitfalls, you’re almost the proud owner of a newly flashed BIOS. Almost, because directly after the flash (always signalled by the flashing software) you should shut the machine down, let it cool a bit, disconnect it from the power and consult the manual on how to erase the CMOS – this is to insure you don’t get garbage settings in your BIOS that might be hazardous. It’s most commonly done by shorting the Clear CMOS jumper and/or removing the bttery – again, the manual is indisposable. After that’s done, replace the battery, plug the machine back in, power it up, enter setup, restore your usual settings (and the time-of-day clock, which will get wiped in case you removed the battery), restart, and if you’ve done everything by the book, you’ll boot into your OS. Congratulations, you’re now the proud parent of a flashed motherboard. You might or might not detect an immediate increase in performance or stability – but even if performance stays as it had been before, all is well, so long as stability stays the same as well. Whatever prompted you to flash the BIOS is hopefully now fixed, and you’ve learned another skill you can keep in your mental utility belt, one that has more application than just BIOS flashes…

Warning: This is a self help guide. A bad BIOS flash can permanently disable your motherboard. If you dont know what your doing get a professional to do it. Use this guide at your own risk.

 
Written by Boris M