Asus DSBF-DM/SAS - Manual (Page 73)

ASUS DSBF-DM Series 4-5
The recovered BIOS may not be the latest BIOS version for this motherboard.
Visit the ASUS website (www.asus.com) to download the latest BIOS file.
Download and rename the file to “BIOS.WPH” before updating the BIOS.
7. Press the power button for more than four seconds to turn off the system.