How to Flash BIOS Without a Battery

By Ken Burnside

Updated February 10, 2017

To flash the BIOS of a laptop without a charged battery, you need to run the BIOS update from a bootable USB drive before Windows loads.
i flash drive image by AndreyPS from

Flashing, or updating, the BIOS of a computer is done to remedy problems with system stability, or to allow the computer to accept larger hard drives or faster CPUs. On many laptops, the BIOS will not update if the battery is not charged, which can be a problem. This usually prevents the BIOS from being flashed from within Windows. BIOS updates are distributed as small executable files. Fortunately, there's a way around this, but it involves booting the computer to a limited OS.

Download your BIOS update from the manufacturer's website, and put it someplace where you'll find it again.

Back up any contents on the USB thumb drive that you want to keep, or use an older USB drive that you no longer use.

Plug the USB thumb drive in a convenient USB port.

Click on the "Start" menu and enter "CMD" in the search field, then hit "Ctrl," "Shift" and "Enter" – this will open a "Command" prompt (DOS-style window) that's elevated to "Administrator: privileges.

Type "DISKPART" and hit "Enter," then type List Disk and hit "Enter." It will give the list of your disk partitions, and will give you the drive numbers of all of your USB disk drives.

Type "Select Disk 'N' " where you replace 'N' with the number you saw in the prior step. If your USB thumb drive is drive 1, you'd enter "Select Disk 1." If it were disk 2, you'd type "Select Disk 2." Hit "Enter."

Type "Clean" and hit "Enter." This removes all information from the thumb drive.

Type "Create Partition Primary," and hit "Enter." This creates a partition on the drive.

Type "Select Partition 1" and hit "Enter," then type "Active" and hit "Enter." This makes the partition you just created active.

Type "Format FS=NTFS" and hit "Enter." This will format the thumb drive with the NTFS file system.

Type "Exit" and hit "Enter," then minimize (don't close) the Command Prompt Window.

Insert your Windows installation DVD into the optical drive. Note what drive letter is assigned to both your USB thumb drive and the optical disk.

Restore the command prompt window, and enter the following commands: "D:" (where "D:" is the drive letter assigned to your DVD drive). Press "Enter," then type "cd D:\boot" and press "Enter." This will take you to the "boot" subdirectory.

Type "bootsect /nt60 G:" -- where "G:" is the drive letter of your USB drive. Press "Enter." Close down the Command Prompt window. This will make your USB drive bootable as an NTFS partition.

Copy your BIOS update to the USB thumb drive.

Reboot your system and hold down F2 or F12 (it depends on the manufacturer) to get into the BIOS. On "Boot Order," make sure that "Boot from USB Ports" is enabled.

Reboot your machine with the thumb drive in a USB port. You will see a "Command Prompt" with whatever drive assignment your USB drive has.

Type in the name of the BIOS Updater, and add "/forceit" to the end, then press "Enter." For example, if your BIOS updater were named "PHOENIX-2-3.EXE," you'd type "PHOENIX-2-3.EXE /forceit."

Items you will need

  • USB thumb drive

  • BIOS Update Executable

  • Windows 7 (or Windows Vista) installation disk


This is the procedure for creating a bootable USB drive for Windows Vista and Windows 7. It does not work for Windows XP.