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    Guide to Flashing a BIOS


I have received numerous emails stating, "You keep telling me about 'flashing the Bios', but how do you do that?"  

Excellent question.  It seems I progressed a bit too rapidly and now we need to take a moment to catch everyone up.  Sometimes we all begin to make assumptions, forgetting that some things are not always known.   So...  let us jump in...

The BIOS - Defined

BIOS (basic input/output system) is the program a personal computer's CPU uses to get the computer system started when you turn it on. It also manages data flow between the computer's operating system and attached devices such as the hard disk, video adapter, keyboard, mouse, and printer. 

BIOS is an integral part of your computer and comes with it when you bring it home.  In contrast, the operating system can either be preinstalled by the manufacturer or vendor or installed by a user.  BIOS is a program that is made accessible to the CPU on an erasable programmable read-only memory (EPROM) chip. When you turn on your computer, the CPU passes control to the BIOS program, which is always located at the same place on EPROM.  This is the POST process or "Power On Self Test."

When BIOS starts the POST process starting your computer, it first determines whether all of the attachments are in place and operational and then it loads the operating system  into your computer's random access memory RAM from your hard disk or a floppy disk. 

With BIOS, your operating system and its applications are freed from having to understand exact details, such as hardware addresses, about the attached input/output devices. When device details change, only the BIOS program needs to be changed. Sometimes this change can be made during your system setup. In any case, neither your operating system or any applications you use need to be changed. 

Although BIOS is theoretically always the intermediary between the CPU and I/O device control information and data flow, in some cases, BIOS can arrange for data to flow directly to memory from devices, such as video cards, that require faster data flow to be effective.

Originally, the EPROM chips used in a PC were printed circuits that were pressed into the slot on the motherboard or soldered on.  Then a few years back, the Bios manufacturers begin to use erasable programmable EPROM chips for the Bios.  The reasoning was to allow for easier updates to the central core BIOS.  Why is this important.  In the past, you would either replace the motherboard or at least the BIOS chip if you needed to upgrade the  basic system programming.  Now,  it can be done with a simple software upgrade that erases the existing BIOS code and then writes a new code to the BIOS EPROM chip.  This process of erasing and writing new code is called "FLASHING."   The Flash Bios often allows a motherboard manufacturer to add features to a BIOS for hardware and settings they did not consider when the motherboard was manufactured, such as larger hard drives, faster CPUs, even specialty devices like ZIP drives.   A Flash Bios can even be offered to correct errors in the code of the original BIOS, called BUGS.

We have an excellent explanation of all the basics of the BIOS and CMOS:



Where to get a Bios Flash Upgrade

Today, we have three major companies who build BIOS chips and program them:  AWARD, AMI and PHOENIX.  You should also know that AWARD was recently purchased by PHOENIX and they no longer sell BIOS chips to motherboard manufacturers.  There are some other off brand manufacturers, but you rarely see their product on a motherboard.  There also are companies that sell replacement BIOS chips, such as Mr. Bios, though the need for these replacement chips has dropped to nothing with the advent of FLASH BIOS.

The first thing you need before you begin is the FLASH upgrade software for your motherboard.  An upgrade is not found at AWARD Bios, AMI Bios or Phoenix Bios' web site.   They are in the business of selling to motherboard manufacturer's and not the general public.  The Flash Upgrade for your motherboard is always supplied by the motherboard manufacturer.  You can nearly always download these upgrades from their web or FTP site.  We maintain a list of motherboard manufacturer's web sites for this purpose.  If you computer was built by a company such as Micron, Gateway, IBM, Packard Bell and others...  often you can find the BIOS Upgrade file on their web site.

Simply write down the version number of your Bios, this can be read above the memory test during the beginning of the POST process when you start your computer.  Also, determine the model of the motherboard you  are using.  These two items are all you will need to find the upgrade for your motherboard on the manufacturer's web site.

The FLASH UTILITY is nearly always  included in the Flash upgrade file you will download.  So, download it first and examine the contents of this file before you begin searching for a Flash Utility file.

- the process -

Okay... you have downloaded the file, unzipped it and discovered it contains three files:  the Flash Utility file,  the upgrade data file and an instructions README file.

READ the instructions file and follow it in detail.  I have seen a couple of people take for granted they know how to flash a BIOS only to find a new requirement and they are stuck with a mess.  READ the INSTRUCTIONS.

Typically, you will need two floppy disks.  One disk is your Boot disk with an operating system and the other contains your Flash Utility and the Upgrade file.  You might be able to put all this on one floppy, but I recommend against  it.  When you Flash upgrade your BIOS, one option is to make a backup copy of your existing BIOS code.  You will want to do this and need room for the Flash Utility file to store your old Bios code.

Next, start your computer and enter the CMOS, the area in the BIOS that contains settings you can modify.  Now look through all the settings and become comfortable with them and even write down any you may need to remember, such as the settings for your hard drive and maybe any Com ports you have turned off to allow a modem to function.

Now, boot your computer with the boot floppy disk, I always use a simple operating system like MS Dos v6.  You can use any that you have on hand: MS Dos, OS/2, Win95/98/NT...  it is not important.  The system only needs the command operator in order to run the Flash Utility file.   Then, insert your Flash floppy disk.  The first thing you should do is read and write down the EXACT name of the Flash Upgrade file, this is usually something like: be6_mu.bin   (this is the name of the one for my ABIT BE6 motherboard).  You will be required to type this in during the upgrade process and you will need it.

Just execute the Flash Utility and follow the instructions on the screen.  Be sure to make a backup of your existing BIOS when prompted.  The name of this backup is not important to anyone but you, so use a name that is easy for you.

I highly recommend that even if you have read the instructions for flashing your Bios that were included, you should also print them out so you have them handy for reference.

After you have finished this process, hopefully with success, all that is need to do is remove your boot disk and reboot the computer.  You will need to enter the CMOS during the POST phase and make all the changes your CMOS requires in order to use the hardware on your system, such as identify your hard drive or turn off a Com port so your modem does not conflict with it.

Now, you should be done and all set.

Some final notes:  This process sounds simple, but  should it fail during the process, you could have some extreme problems.  You could be left with a BIOS chip with no programming and in that case it will not be able to start the computer again.  This will require either replacing the BIOS chip or the motherboard.  This is not always a safe and simple operation.  Be sure you are comfortable with this level of upgrading.  It maybe something you wish to have a professional do for you.  But, once you have done this procedure, you will understand and feel more confident should the need arise to Flash Upgrade another computer.  Just never become to complacent with this procedure...  it can be ruinous to your motherboard.

Tip of the Week

When you are in the middle of Flash upgrading your BIOS the last thing you need is a power outage.  Imagine the power goes out right as you are writing in the new BIOS code.  The system is left without a BIOS, you are then either replacing the BIOS chip or the motherboard.

One of the most important things you can do during this process is to have the computer connected to a strong UPS.  You will want a UPS that can support the computer for at least 15 minutes should the power suddenly go out.  Most people do not consider this and get away with it... just know that it is a risk.  I always use a strong UPS and I never worry about the power going out.

Have fun




Which Bios version to download?

Okay, you went to the website and found that there are 2 or more versions of upgrades for your Bios.  Do you download all of them, using them one at a time?


Just download the latest one, it has all the previous upgrades included.





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