Why does my computer reboot during a BIOS update?
If your computer freezes or reboots while a BIOS update is being written, your computer's BIOS data may become corrupted, causing your computer not to boot.
Reset the BIOS
Because the actual BIOS is corrupted it must either be reset or replaced. With some computer motherboards, it may be possible to restore the default BIOS settings using a jumper on the motherboard. Refer to the computer manufacturer or motherboard manufacturer manual to see if this is possible. Often the jumper will be labeled as Reset BIOS.
The "reset BIOS" jumper should not be confused with the "reset CMOS" jumper, as it only resets your stored CMOS values stored in the CMOS battery, and not the actual flash BIOS. Resetting the CMOS with the Reset CMOS jumper or removing the battery and putting it back into the computer will not resolve this issue.
Replace BIOS
If you're unable to reset your BIOS, or your motherboard does not have this jumper, contact the OEM (original equipment manufacturer) or motherboard manufacturer for further suggestions. Often, you can get a replacement BIOS chip if yours no longer works.