How to Update ASUS BIOS Without a Battery (The F11 Trick)

This trick allows you to bypass the BIOS security check that prevents you from updating the BIOS without a battery.

⚠️ CRITICAL WARNING
Ensure the AC adapter remains securely connected at all times.
If the power is cut during the update process, your laptop may be permanently damaged (bricked). Proceed at your own risk.

Instructions

To update the BIOS using the F11 trick, follow these steps:

1. Prepare the USB: Connect the USB drive containing the BIOS update file to your laptop.
2. Enter BIOS: Power on your laptop and press F2 to enter the BIOS setup.
3. Open Utility: Navigate to and open the EZ Flash utility.
4. The F11 Trick: When you are at the screen where you select the file source:
   • Press and hold the F11 key.
   • While holding F11, select the BIOS update file from the USB drive and press Enter.
5. Wait: Continue holding F11 until the progress bar appears or the update actually begins.
6. Finish: Once the BIOS update is complete, your laptop will restart automatically.

Why this works (and why the check exists)

ASUS blocks BIOS updates on low or missing battery for a real reason: a BIOS flash writes to the motherboard’s firmware chip, and if power dies mid-write, the chip is left half-programmed — a bricked board that won’t POST. The battery is meant to be a backup so a yanked AC adapter doesn’t kill the flash. The F11 trick is undocumented — a workaround reported by users, not an ASUS feature — and it appears to bypass the battery-safety check that EZ Flash normally enforces. That’s exactly why the AC-adapter warning above isn’t optional: if it’s removing that safety net, you must not lose power for even a second.

A safer alternative, if your board has it

Some ASUS desktop motherboards support USB BIOS FlashBack — a dedicated recovery button that flashes firmware with the machine powered off entirely, no battery or even CPU required. It’s a separate, officially supported feature (not the same mechanism as the F11 trick, and not present on most laptops), so check your exact model’s manual — if you have it, it’s the safer route.

Note

Please note that this trick is not officially supported by Asus and may not work on all laptop models. If you are not comfortable taking the risk of updating the BIOS yourself, it is best to take your laptop to a qualified technician. (For a different ASUS-laptop headache — ACPI errors when installing Linux — see fixing ACPI BIOS errors on Ubuntu.)

Reference: Reddit - BIOS Update Without Battery