BIOS Flashback helps you to update to new or old motherboard UEFI BIOS versions even without a CPU or DRAM installed. This is used in conjunction with a USB drive and the flashback USB port on your rear I/O panel. There may be several reasons behind this, like faulty current software, so going back to a stable version, etc. There are a few ways that you can use the BIOS FlashBack. Some motherboards and systems will have a BIOS FlashBack button.