The BIOS firmware supports both legacy BIOS and Unified Extensible Firmware Interface (UEFI); the default setting is Legacy. Oracle VM only supports Legacy BIOS mode at this time. For Oracle VM, you must make sure that BIOS is set to legacy mode before you do the OS installation.
If the BIOS mode has been set to UEFI mode, use the following procedure to set it to Legacy mode.
POST messages appear on the console.
The BIOS Setup Utility main screen appears.
The Boot Menu screen appears.