The BIOS (Basic Input / Output System) is the software code that first runs when the PC powers on. It contains all the information necessary to initialize almost all the hardware components of the PC. Normally, when you switch on the PC, the BIOS performs a Power on Self Test, or POST as it is called. This is a series of diagnostic tests on the RAM and other Hardware. It also initializes all the hardware devices such as the hard disk, memory, video and other hardware, identifies and reserves memory addresses for all the IRQs and ports available on the motherboard, and calls a small operating system program known as the boot loader. The boot loader, using the BIOS information among other things, starts calling the programs that will load the OS. And finally, the OS uses the BIOS information to take control over the hard ware devices.
Mother board manufactures use the BIOS to define settings for the various hardware components including the hard disk, RAM, CD-RAMs, I / O ports etc. These are generally set at the factory and are what is called the Setup Settings or the BIOS Setup Default Settings.
The BIOS software code and all the settings for the PC are stored on a memory chip that's continuously supplied with the power by a battery. The battery also powers a real time clock that keeps accurate times. Here, these settings are retained even when the power is switched off.
Mother board manufactures and BIOS vendors frequently release updates, which can be "flashed" to the BIOS. In some troubleshooting cases, your only option is to update the BIOS.
To enter the BIOS setup, you'll need to press [Delete], or something similar, when your computer is booting up. Depending on the PC, the key may be different – [Esc], [F1], [F10]. Etc.
Updating the BIOS and other firmware
Taking advantage of the capabilities offered by EEPROM, motherboard manufactures have begun releasing new versions of the BIOS with greater frequency these days. There are many reasons that an update to the BIOS may be required: the new version offers better stability, compatibility or performance; new technical break thoughts require new features in the BIOS; a device attached to the computer may not function without the newer version; and increasingly, flashes fix some problems in the earlier version of the BIOS.
Just as the PC motherboard has a BIOS chip, so do other hard ware components and peripherals. These include things such as the video card, the CD-ROM / RW, DVD-ROM / RW, etc. Generally, the BIOSes on these are known as firmware. And just as the PC BIOS can be updated, the BIOS of these devices can be updated, too. While we only cover flashing the PC BIOS, the procedure is pretty similar for other firmware. In all cases, make sure you have all the information and the procedure down before the procedure.
Identify If Your BIOS is flashable
The first step is to identify if you have a flashable BIOS. Peel the sticker off the BIOS chip and note down the model number. Go to the motherboard manufacturer's Web site and search for the model and whether it's flashable. Once you've determined that you have a flashable BIOS, we are in business.
Note Down The Current Settings
The next step is to note down all the current BIOS settings. Switch on the PC and enter your BIOS setup. If you have a printer attached and the print screen button works, go to each and every menu page and print out the settings. Otherwise, note it down by hand. In case something goes wrong, you will need to refer to these set things to reset BIOS.
Get the latest BIOS updates
Once you've copied down all your settings, the next step is to identify the latest updates for your BIOS. To do this, go to your motherboard manufacturer's website and look up BIOS updates for your mother board model, make and number. Download the correct update from the site. Download the flash program that will 'flash' the update onto your BIOS chip. Typically, the update and the flash program will be zipped together.
Create two MS-DOS boot floppy disks
Ensure that you're on a reliable power supply and that your floppy drive is not defective. Copy the flash program to a new floppy disk formatted as on MS-DOS startup disk .. Keep second formatted disk also ready.
Back up your current BIOS
Ensure that the floppy device is the first boot device in your BIOS settings. Insert the first floppy and reboot the system. You will taken to a DOS prompt (A 🙂 from where you should type in the name of the flash program. On the screen that appears, select the option to save your current BIOS to the first floppy disk where you only have the flash program. This will serve as a back up in case something goes wrong with your update and you need to revert to your old BIOS.
Flash the BIOS
Copy the flash program and the BIOS update file to the second floppy disk. Verify that the update file has been copied correctly. Reboot the system with the floppy inserted in the floppy drive. At the A: prompt, type out the name of the flash program followed by the BIOS update file name. A screen appears showing you the update file that will be flashed to the BIOS. Confirm it. WAIT will the BIOS flashed. You will be informed when it is over and asked to exit. Once you are back at the DOS prompt, remove the floppy and reboot the system. If everything has gone off well, you should get the normal POST screen.
Configure the new BIOS
After flashing your BIOS with new version and rebooting, enter the BIOS setup. The first step is to load the factory defaults. This will ensure that all the new options will default to the factory setting, which under normal circumstances should be safe. After loading the defaults, the next step is to configure the BIOS to your system specific settings. Pull out the screen shots you printed earlier and the key in all the settings there. You may, of course, change any of those settings if you are sure about what you are doing. As a first step, however, it is better to use the old settings and check if your system boots up to the OS and everything is working normally.
Recovering from a Corrupted Flash
Some of the main reasons for the flash BIOS corruption are incompatible add-on cards, aborted flash updates due to power fluctions, or improper BIOS image.
If your flash attempt fails, do not panic! Such failures are often reliably recoverable, as most newer BIOS codes today include a Boot Block Protection option. A BIOS of this type has two distinct parts. The First Boot Block part contains information needed to initialize only critical system devices such as floppy drive, processor, memory and ISA video devices. This part is write protected and can not be overwritten by flashing. The second part is the flashable part, known as system block, and contains all the information needed to initialize other system devices such as video, storage, COM ports, input devices, other peripherals, and performing the POST.
To recover from a corrupted flash, you need to be able to boot into the floppy where you have the flash program and the BIOS file you want to flash. An ISA video card is preferred, but if you do not have one, you can still do it. If you have the ISA card then you will not be able to see what you are doing. Reboot the system to the DOS prompt and repeat the steps above for flashing, or the steps specified by your mother board manufacturer.
If you do not have an ISA video card, create an autoexec.bat file, which will run when you boot into the DOS system. Use Notepad to create a single line entry which will contain the flash program name followed by the update file name along with any switches that are specified.
This instructions DOS prompt to run aotuexec.bat when the system boots up and run the awd802.exe flash program using the backup.bin BIOS update file. The switches are various options specific to the flash program, with the last switch instructing the program to reboot once flashing is completed.
Copy the autoexec.bat file to the floppy with your flash program and the BIOS update file you want to use. The floppy should only contain the basic DOS system files, and should not have any other files that may auto-load on start up and interface with the flashing.
The example above is for an Award BIOS update. While the parameters will most likely differ for your particular BIOS version, the general approach remains the same:
o Create a DOS system floppy
o Copy the flash program and the BIOS update file
o Create an autoexec.bat batch file with a single line entry instruction DOS to flash the BIOS when system starts up
Be sure to read up the manufacturer's instructions on each switch parameter and how they should be used.
Source by GR Brindha Shivakumar