: The Acer H61H2-AD uses an AMI (American Megatrends) Aptio 4 BIOS. You need to be aware of a major pitfall: Acer does not provide direct public BIOS updates for this motherboard. Flashing a BIOS from a different computer model (even if the physical motherboard looks identical) carries a high risk of bricking the board. There are numerous reports of flashing tools failing specifically on this board due to a "ROM file size mismatch" error. Do not attempt to flash a BIOS unless you have the exact, verified update for your specific pre-built computer model.