The BIOS Setup Utility in the Oracle Server X6-2 is equipped with a Unified Extensible Firmware Interface-compatible BIOS (UEFI) that can be configured to support either UEFI or Legacy boot modes. Legacy Boot Mode is the default mode. Some operating systems cannot boot in UEFI Boot Mode, so the BIOS setup utility provides the ability to select between UEFI and Legacy boot modes.
If you change BIOS boot modes, the boot candidates from the previously selected mode are no longer available from the Boot Options Priority List in the BIOS Setup Utility. The boot candidates from the new mode appear in the Boot Options Priority List only after you select Save Changes and Reset from the BIOS Setup Utility menu. Use the Oracle ILOM BIOS Backup and Restore function to preserve the BIOS configuration in case you want to switch back to the previously selected mode. For information, refer to the Oracle X6 Series Servers Administration Guide at https://www.oracle.com/goto/x86admindiag/docs.
Most supported operating systems can use either UEFI Boot Mode or Legacy Boot Mode. However, once you choose a boot mode and install an operating system, the installed image can only be used in the mode in which it was installed. For instructions for selecting either UEFI Boot Mode or Legacy BIOS Boot Mode, refer to Using UEFI in Oracle Server X6-2 Service Manual.
The following table describes the BIOS boot modes.