When switching between Legacy BIOS Boot Mode and UEFI Boot Mode (either direction), BIOS settings that affect the Boot Options Priority list settings will be changed. If the boot mode is changed, the boot candidates from the previous boot mode disappear. The boot candidates for the newly changed boot mode appear after you save your changes and reset the host and in the next boot to the BIOS Setup Utility.
Note - When switching between Legacy and UEFI modes, Boot Options Priority list settings will not be preserved. Typically, once a boot mode is selected, there is no need to switch boot modes. However, there is one notable exception: the Pc-Check utility must be run in Legacy BIOS Boot Mode. If boot settings are customized while in UEFI Boot Mode, and you need to run Pc-Check, you should use the BIOS Backup and Restore feature to capture the customized settings prior to switching the boot mode to Legacy BIOS Boot Mode to run Pc-Check. When you return to UEFI Boot Mode, you can use the Oracle ILOM Backup and Restore feature to reinstate your saved settings.
Because the settings for a given mode do not persist after a transition between modes, you should use the BIOS Backup and Restore feature to capture and preserve the BIOS configuration if you intend to switch back to the previous BIOS mode and want to retain your previous BIOS settings. For information about the BIOS Backup and Restore feature, refer to the Oracle Integrated Lights Out Manager (ILOM) 3.1 Documentation Library at http://www.oracle.com/pls/topic/lookup?ctx=ilom31.