The BIOS firmware supports both legacy BIOS and Unified Extensible Firmware Interface (UEFI). The default setting is legacy BIOS. Because VMware ESXi 5.0, 5.1, and 5.5 support both legacy BIOS and UEFI BIOS, you have the option of setting BIOS to either Legacy mode or UEFI mode before you perform the installation.
Note - After you have installed the VMWare ESXi virtual machine software, if you decide you want to switch from legacy BIOS to UEFI BIOS or vice versa, you must reinstall the software.
Before You Begin
Before you begin, ensure that a console connection is established to the server. For details, see Selecting the Console Display Option.
-> reset /System
The BIOS screen appears.
After a few moments, the BIOS Setup Utility appears.
The Boot Menu screen appears.