BIOS update SOP
1. Put files from BIOS package into UEFI bootable USB drive.
2. Power on board with USB drive attached.
3. Select boot for shell loader in USB drive (or Built-in Shell if present).
4. Move operating directory to USB drive (fs1 or other labels)
SHELL> fs1:
5. Enter the directory with BIOS file and update batch
6. To update your current BIOS: fs1>GO.nsh
7. Confirm update procedure is completed without problem
8. Reboot system

Or you can read the detailed tutorial in our wiki.