How to Flash (Update) Your Motherboard’s System BIOS

Recently Bob did an article on finding out the model of your motherboard. Since you usually find out the version of your board’s BIOS at the same time, I thought that an article on updating, or flashing, your BIOS would be a good idea. There were numerous articles on the subject back when I first got into building, and all of them involved a 3.5” floppy drive. Today, nearly all motherboards have multiple options for flashing the BIOS, and normally a floppy isn’t required.

First, what is the BIOS, or Basic Input/Output System?  The BIOS is your motherboard’s firmware, the first code run by your PC when it is turned on.  It identifies, tests, and initializes the system’s hardware…the processor, the video card, hard drive, memory, optical drive(s), etc.  The BIOS then brings the hardware into a known state so that the operating system can be loaded, executed, and given control of the system.  This process is called booting up, which is actually short for “bootstrapping”.   It is often mistakenly called POST (by me too) though the Pre-Operating System Test is only one part of what the BIOS does prior to the operating system launching.  The BIOS is located on one or two EEPROMs (more commonly known as flash memory) on the motherboard.

How to Flash (Update) Your Motherboards System BIOS How to Flash (Update) Your Motherboards System BIOS
The BIOS itself is nearly always licensed from a third party and modified to fit the particular motherboard.  The vast majority of PC motherboards use BIOS from either American Megatrends or Phoenix.

So what does “flashing the BIOS” mean?  Flashing the BIOS means overwriting the BIOS contents with a new BIOS image.  The BIOS is located on rewritable flash memory, hence, “flashing”.

Why flash the BIOS?  When a motherboard is first designed it is given an initial BIOS.  As the motherboard is used, tested, tried with different brands of memory, different processors, etc by the manufacturer’s techs, changes may be made to the first BIOS before the motherboard is ready for release.  For that reason, the original BIOS for a board may be something like version 1.03.

But things don’t end there.  After the motherboard is released for sale, settings are usually changed to accommodate different memory, processors, or just to make the system run better.  Sometimes new options are added to the BIOS settings.  These changes are made over a period of weeks or months.  As significant changes are made, the motherboard manufacturer releases new versions of the BIOS.   This process is often known as the BIOS maturing.  I remember back when I first started building enthusiasts talking about waiting until a motherboard’s BIOS matures before purchasing one.  That was ok several years ago, but things move a little too fast today to wait months before buying something just for that.  And flashing BIOS today is too simple to wait just because of that.

So new BIOS updates could contain something as simple as compatibility for additional memory or additional CPUs, or something as cool as new overclocking settings.  They could contain changes to improve system stability or increase the maximum memory speed.  Once I was very pleasantly surprised to find that the entire overclocking menu had been changed to the same menu that the top-of-the-line motherboard used, which had numerous extra settings, and allowed me an additional 13% overclock over what I was originally getting.

How to Flash (Update) Your Motherboards System BIOS How to Flash (Update) Your Motherboards System BIOS
But there is an aura of fear surrounding the entire thought of flashing the BIOS.  In the past flashing the BIOS was a scary thing…creating a bootable floppy with MS-DOS, getting the BIOS file from the manufacturer…hoping and praying that it was the right one because you were allowed by the system to flash the wrong BIOS image…and if you did you ruined the motherboard.  If the floppy failed or the power went out while the process was taking place,  motherboard was now a big expensive paperweight.

Though even today, if you go to the download section of your motherboard manufacturer’s website, you will see a disclaimer saying something like:

“Update the BIOS only if you have problems and you are sure that the new BIOS revision will solve your problems.  Careless updating may result in more problems with the motherboard!”

I have mixed feelings about those disclaimers.  I realize that they are there for the totally uninitiated who could screw things up while flashing the BIOS, which could change the motherboard from an awesome piece of technology to an expensive doorstop.  But these people will miss out on any cool late additions that the manufacturer may have added to the BIOS.

And these same manufacturers have worked very hard to make BIOS flashing safe.   First, a “boot block” was added to the BIOS, a portion of the BIOS that runs first and must be updated separately.  This code verifies if the remainder of the BIOS is correct and complete.   If the boot block detects any corruption in the main BIOS, it will typically warn the user that a recovery process must be initiated so the user can try flashing the BIOS again.

Next, some manufacturers placed a second BIOS on the EEPROM as a backup.  This is often used in conjunction with a crash-proof BIOS, where if there is a problem with the primary BIOS, the system will boot with the original settings.

Gigabyte has gone so far as to place two EEPROMs on the board, each with two copies of the BIOS.  That is about as safe as you can get.   So flashing the BIOS is infinitely safer than it has ever been.  There is no reason to be afraid.