The BIOS firmware supports both legacy BIOS and Unified Extensible Firmware Interface (UEFI). The default setting is legacy BIOS. Because the Windows Server 2008 and 2012 operating systems support both Legacy BIOS and UEFI BIOS, you have the option of setting BIOS to either Legacy BIOS Boot Mode or UEFI BIOS Boot Mode before you perform the installation.
Note - After you have installed the operating system, if you decide you want to switch from Legacy BIOS Boot Mode to UEFI BIOS Boot Mode or vice versa, you must remove all partitions and reinstall the operating system.
-> reset /System
When prompted, enter y to confirm:
Are you sure you want to reset /System (y/n)? y
Performing hard reset on /System
The BIOS screen appears.
After a few moments, the BIOS Setup Utility appears.
The Boot menu screen appears.