Asus P4S8X-X - Manual (Page 38)

2-6 Chapter 2: BIOS information
6. When prompted to confirm the BIOS update, press Y to start the update.
7. The utility starts to program the new BIOS information into the Flash ROM. The
boot block is updated automatically only when necessary. This minimizes the
possibility of boot problems in case of update failures. When the programming
is done, the message “Flashed Successfully” appears.
8. Follow the onscreen instructions to continue.
If you encounter problems while updating the new BIOS, DO NOT turn off the
system because this may cause boot problems. Just repeat the process, and if
the problem persists, load the original BIOS file you saved to the boot disk. If
the Flash Memory Writer utility is not able to successfully update a complete
BIOS file, the system may not boot. If this happens, call the ASUS service
center for support.