How to Install a BIOS Update on an ASUS Motherboard

The basic steps for updating ASUS BIOS

To update your ASUS BIOS, you download the latest version from ASUS's support website, save it to a USB drive, restart your computer into the BIOS menu, and use the built-in flash utility to write the new file. The whole process takes 10 to 20 minutes, though the actual flash takes only a few minutes. Most ASUS boards made in the last decade support this method, which is safer than older approaches because it does not require a working operating system.

The key difference between ASUS boards is whether they have a dedicated button to enter the flash utility directly, or whether you must navigate through the BIOS menu to find it. Newer boards often have a button labeled "BIOS FlashBack" or similar on the rear I/O panel, which skips the menu entirely. Older boards require you to enter the BIOS setup screen first.

Key Takeaways

Download the BIOS file from the ASUS support page for your exact motherboard model, not a similar one, because files are not interchangeable between models.
Format a USB drive to FAT32, place the BIOS file in the root directory, and rename it to match what your motherboard expects — usually something like ASUS_Z790.CAP — because the flash utility searches for a specific filename.
Plug the USB drive into a rear USB port, not a front panel port, because the BIOS cannot always read front ports reliably.
Do not turn off the computer or unplug the power cable while the flash is running, because an interrupted update can leave the BIOS unbootable and require a recovery process.
Back up your current BIOS settings before you start, using the "Save to File" option in the BIOS menu, so you can restore them afterward if needed.

Finding and downloading the correct BIOS file

Go to the ASUS support website and search for your motherboard model. You can find the exact model name on the board itself, in your system information, or on your purchase receipt. Type it into the search box — do not guess or use a similar-sounding model, because BIOS files are not compatible across different boards.

Once you find your board's support page, look for the "BIOS" or "Firmware" section. ASUS lists versions in reverse chronological order, with the newest at the top. Read the release notes for the version you want to download. Most people should download the latest stable version unless the notes describe a problem that does not affect them. Download the file to your computer — it will be a .CAP, .ROM, or .BIN file, usually between 5 and 20 megabytes.

Preparing the USB drive

Use a USB drive that is at least 1 gigabyte in size and is currently empty or contains only files you do not need. Plug it into your computer, open File Explorer or Finder, right-click the drive, and select "Format". Choose FAT32 as the file system — this is the format that BIOS flash utilities can read. Do not use NTFS or exFAT, because the BIOS will not see the file.

Once the drive is formatted, copy the BIOS file you downloaded to the root directory of the USB drive — meaning the top level, not inside a folder. Then check the filename. ASUS boards expect a specific name, which is usually printed in the BIOS menu or in the release notes. Common names are ASUS_Z790.CAP or Z790.CAP or ASUS.CAP. If your file is named something else, rename it to match. If you are unsure of the correct name, check the release notes PDF that came with the download, or look in your BIOS menu under the flash utility — it often displays the expected filename.

Entering the BIOS and starting the flash

Shut down your computer completely. Plug the USB drive into a rear USB port — USB 2.0 or 3.0 both work, but use a rear port because front panel connectors are sometimes unreliable. Power on the computer and immediately press the key to enter the BIOS setup. This key is usually Delete, F2, or F12, depending on your board — it is displayed on the boot screen for a few seconds. If you miss it, shut down and try again.

Once you are in the BIOS menu, look for an option called "BIOS FlashBack", "EZ Flash", "Instant Flash", or "Update BIOS". The exact name varies by ASUS board generation. Navigate to it using the arrow keys and press Enter. The utility will scan your USB drive for the BIOS file. If it finds the file, it will display the version number and ask you to confirm. If it does not find the file, check that the filename matches what the utility expects, that the file is in the root directory of the USB drive, and that the drive is formatted as FAT32.

Press Enter or Y to confirm the flash. The screen will display a progress bar. Do not turn off the computer, unplug the power cable, or press any keys while the flash is running. This usually takes 2 to 5 minutes. When it is complete, the board will either restart automatically or ask you to press a key to restart.

What to do after the flash is complete

After the computer restarts, it may take longer than usual to boot, or it may display a message saying the BIOS has been reset to defaults. This is normal. Let it finish booting into Windows or your operating system. Once you are logged in, restart the computer again and enter the BIOS menu to verify that the new version is installed. The version number is usually displayed on the first screen of the BIOS menu.

If you backed up your BIOS settings before the update, you can now restore them. Enter the BIOS menu, find the "Load from File" or "Restore Settings" option, and select your backup file from the USB drive. This will restore your custom settings without affecting the new BIOS version. If you did not back up your settings, you will need to reconfigure any custom options you had changed, such as RAM speed, CPU voltage, or boot order.

Troubleshooting a failed or stuck flash

If the flash fails partway through, the BIOS may be corrupted and the computer may not boot. ASUS boards have a recovery method for this situation. Most newer boards have a dedicated button on the rear I/O panel labeled "BIOS FlashBack" or "BIOS Recovery". With the computer powered off, hold this button for 3 to 5 seconds while the power supply is on but the computer is off. The board will enter recovery mode and attempt to flash the BIOS file from the USB drive automatically. This process is slower than a normal flash and may take 10 minutes or more.

If your board does not have a recovery button, or if recovery mode does not work, you may need to clear the CMOS to reset the BIOS to factory defaults. Locate the CMOS battery on the motherboard — it is a small coin-shaped battery, usually silver. Power off the computer, unplug the power cable, and remove the battery for 10 seconds. Reinsert the battery, plug in the power cable, and power on. The BIOS will be reset, and you can attempt the flash again. If the board still does not boot after recovery, contact ASUS support with your board model and the version you were trying to flash.

When not to update your BIOS

You do not need to update your BIOS unless the release notes describe a problem that affects you, or unless you are installing a new CPU that requires a newer BIOS version. Updating the BIOS carries a small risk — if the power fails during the flash, or if the file is corrupted, the board can become unbootable. If your system is stable and working well, there is no benefit to updating.

Check the release notes before you download. If they mention fixes for features you do not use, or for hardware you do not have, you can safely skip that version. ASUS releases BIOS updates frequently, and you can always update later if a problem arises. The only exception is if you are installing a new CPU — some boards require a BIOS update to recognize newer processors, and you may need to update before the new CPU will work at all.

Frequently Asked Questions

Can I update the BIOS from Windows instead of using a USB drive?

Some ASUS boards have a Windows-based flash utility that you can download from the support page and run from your operating system. This is convenient, but it is riskier than USB flash because a crash or power failure during the update can corrupt Windows itself. Most people should use the USB method instead. If you do use the Windows utility, make sure your computer is plugged into a UPS or battery backup, and close all other programs before you start.

What if my computer will not boot after the BIOS update?

First, try restarting the computer — sometimes the first boot after an update takes longer than usual. If it still does not boot, try the BIOS recovery process described above using the dedicated recovery button or by clearing the CMOS battery. If neither of those works, your board may have a hardware problem unrelated to the BIOS update. Contact ASUS support with your board model and a description of what happened.

Do I need to update the BIOS if I am just upgrading my RAM or graphics card?

No. BIOS updates are only necessary for CPU compatibility, or to fix specific bugs that affect your hardware. Upgrading RAM or a graphics card does not require a BIOS update. Check the release notes to see if the update mentions your CPU model or a feature you use. If it does not, you can skip it.

Is it safe to update the BIOS while other programs are running?

No. Close all programs, including antivirus software, before you start the flash. The BIOS update needs full control of the hardware, and background programs can interfere. Restart your computer, plug in the USB drive, and begin the flash immediately after booting.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.