Your computer's BIOS - Basic Input/Output System - is a chip on the motherboard which contains enough information to allow it to start up before the main operating system begins to load. Here's everything you need to know about how to update a PC BIOS, whether traditional or the newer UEFI standard. See also: How to install Windows 7

When you should update a PC's BIOS

Before you start, heed this warning: if something goes wrong during the BIOS update, your computer could be rendered useless. If there's a power cut, or the computer gets turned off while updating, it could mean that it's unable to boot at all. 

For this reason, it's worth checking whether you really need to update your BIOS. Read the release notes of the latest version (and each version back to the one currently installed) to see whether it will add the features you need or fix a problem you're having. If not, there may be little point in taking the risk by updating.

Sometimes you will need to update the BIOS in order for the motherboard to properly support a new processor or other hardware, or to fix bugs and improve stability or performance.

In most cases, nothing will go wrong at all, but it's important to know that there's an associated risk and not to treat the process too lightly.

How to update the BIOS

It's good to have a spare copy of all important files from your PC before you start. Though a failed BIOS update doesn't endanger the data on your hard drive directly, you will be able to access your files and continue working with them on another PC or Laptop without delay if you have a backup on a removable drive.

Similarly, creating a backup of your BIOS is also a good idea. Sometimes this will be done automatically as part of the updating process, but if it requires you to do it manually, be sure not to skip this step. 


Step 1: Identify the make and model of your motherboard

The easiest way is to look in the user manual of your mainboard. Additionally, the full model name –such as P5E3 Deluxe – is usually found somewhere on the board itself. It’s important to get the full name as there are ususally subtly different versions. Plus, you should note down the revision number – for example REV 1.03G as it may require a different BIOS file to previous revisions.

If you have a laptop, you need only to find the make and exact model of the machine itself.

Step 2: Find out the current BIOS version

Identifying your BIOS version is easy: hold down the Windows key+ R to bring up the Run command prompt and type in msinfo32. In the System Information window which appears, select System summary on the left and look for the entry BIOS Version/Date on the right.

Step 3: Download the latest BIOS file

Head to the motherboard or laptop manufacturer's website and look for a support link. You should be able to search for the model and see a list of available downloads, which might include manuals, drivers and BIOS files.


If a BIOS update is indeed among them, it‘s time to check the numbers: Did you type in the name of your mainboard correctly? Is the update newer than your current version? And if so, does it state that your specific problem will be addressed in the documentation? If everything applies, upgrading your BIOS is likely a worthwhile idea.

Most update packages consist of a flash program which is responsible for the setup and the actual BIOS-Update, often accompanied by a text file of some sort detailing the release notes.

At this point, it's well worth reading any instructions on the manufacturer's website about the exact updating process for your BIOS. They do vary, and you may need to configure some things before starting the update process, such as disabling secure boot modes and fast boot modes. 


Step 4: Updating in Windows

These days it's common to download an executable file which runs in Windows and updates the BIOS with only a couple of clicks. The process is automatic and doesn't require you to type any commands at a prompt. 

However this isn't always the case, even for new motherboards or laptops, and it's possible that you will have to create a bootable CD or USB drive and copy the files to that. Even if the BIOS update is designed to be run from a floppy disk you can usually use a USB flash drive, but you may need to first enter the BIOS to tell it to boot from the CD or USB drive instead of the hard drive. Typically you won't need to as a PC or laptop will be set up to look for a removable disc or drive before trying to boot from the hard drive. Alternatively, look for a 'Press F10 for boot options' or similar as your computer is starting to bring up a list of drives.

Step 5: How to make a bootable USB drive

Update the BIOS with a USB flash drive

To make a USB drive bootable, you will need a utility such as Rufus or Unetbootin. You will need a ISO image as well, and FreeDOS is the most appropriate for installing BIOS updates. Once you have the bootable drive, copy all necessary BIOS and update utility files onto it which you downloaded from the manufacturer's website

BIOS update with a floppy disk

In the unlikely event you have to update from a floppy, a bootable disk can be created by entering format a: /s into the command prompt (in DOS). In Windows, this is arguably slightly more complicated. Insert a floppy disk into your drive and right-click the corresponding drive symbol inside the Windows Explorer (usually A:). Choose Format followed by Create MS-DOS boot disk. Delete all files except, Io.sys and Msdos.sys from the disk, even those that are invisible. To do so, enter the Control Panel and click on Folder Options. Under the View tab check Show hidden files, folders and drives and uncheck Hide protected operating system files. Again, copy the necessary BIOS files to the disk along with any executable files.

See also: How to access floppy disks and other obsolete media

Step 6: Performing the BIOS update

In Windows

To begin with the update proper, start up the Live Update utility of your respective manufacturer – in our case Asus Update. As mentioned in step 6, you often get the option of doing a backup of your BIOS beforehand. Look for an entry along the lines of "Save current BIOS data" and select a folder of your choice to store it in. If something happens to go awry during the updating process, refer to step 10 for instructions on how to use it.

To download the update, you will now need to look for an option that has a similar name to "Update BIOS from the Internet" and click on it. If the default server does not respond, you can usually find an "Auto Select" option nearby to switch to another one. In the unlikely event that a newer version of your updating software is available, you will likely be required to download it first, so don't worry about that. After finding a newer version of your BIOS software, download it and click on "Update BIOS from a file" to select it for the process. Depending on your updating utility, you might arrive at a final page that compares the information of your old BIOS  version with the new one – this is your last chance to check of everything is in order. If you are absolutely positive to start to process, click on "Update" or "Flash".  After the process is done, reboot your PC for the changes to take effect.


It's finally time to use that USB stick or floppy disk that has been prepared in step 3 and 4. Insert it into the USB port or floppy drive and turn your PC on. If you have adjusted your boot sequence accordingly as described in step 7, your PC should load it up automatically, resulting in the display of a DOS prompt. Enter the name of the flash tool – in the case of an Award-BIOS "awdflash" – and press Enter. The flash tool should now give out some information about your BIOS-ID and the age of the build. First, take a look around and evaluate your options at the lower area of the screen. If you can, create a backup of your BIOS before continuing on (usually with the B-key). Otherwise, select the file you wish to update your BIOS with, wait for it to compatibility analysis to finish and confirm the updating process.

In the BIOS

Instead of booting from DOS, enter the BIOS UI instead and search the menu for an option like "EZ Flash 2" (try the tools section). Conveniently, the installation assistant provided is usually quite similar, if not identical to the one in DOS, so just refer to the above section for guidance.

Step 7: Check BIOS settings

Once the flashing tool has successfully finished updating, you can theoretically restart your PC immediately and resume working with the new BIOS. However, we recommend checking some things first.


First, enter the BIOS using the appropriate key, which should be displayed during boot up. Check the main settings to ensure the date and time are correct, that the boot order is how you want it, and make sure everything else looks correct. Don't worry too much about the advanced settings unless you experience any problems. If you noted down your previous BIOS settings or know them by heart, configure them accordingly. Make sure to save your changes before exiting again.

Also take a look at: PC startup won't proceed further than the BIOS screen


Checking the drivers

More often than not, the point of a BIOS update is improved hardware compatibility. Consequently, after applying the update, Windows is usually confronted with a number of previously unknown devices at once. To check if all drivers have been installed correctly, take a look at Device Manager in the Control Panel. If there are any yellow exclamation marks left, it's best to check for appropriate drivers manually. Make sure your processor is showing correctly, with the right number of cores.

Step 8: The update has failed – what now?

In spite of every precaution and safety measure, the update can still fail - whether it be due to unexpected incompatibility issues, an unfortunate blackout or the cat walking on the keyboard. Here's what to do: If still functional, do not turn your PC off. This applies to both DOS and Windows: Close the flash updating tool and restart the updating process anew to see if it works. If you made a backup of the BIOS, you can try selecting that file to isntall instead of the newer one. Some motherboards have a backup BIOS, so you may be able to restore the information from that: check your manual or instructions online for how to do it.

In case that doesn't do the trick you may want to try contacting the manufacturer of your mainboard. They will propably either ask you to send the BIOS chip in directly or redirect you to a hardware specialist who can reprogram it back to factory default. Unfortunately, this it unlikely to be cheap.

Alternatively, it is also worth checking out whether or not the manufacturer sells its BIOS chips directly over an online shop, which more often than not turns out to be much cheaper. An example for ASUS mainboards can be found here.