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Oracle® X6 Series Servers Administration Guide

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Updated: September 2017

Legacy BIOS Boot Mode and UEFI Boot Mode

The server is equipped with a Unified Extensible Firmware Interface (UEFI), which can be configured to support either UEFI or Legacy BIOS Boot Mode. Legacy BIOS is the default boot mode, and should be used with software and adapters that do not have UEFI drivers.

When you change the server boot mode, the change takes effect at the next server reset. If you intend to switch boot modes, you should back up the current UEFI configuration. For instructions on backing up current firmware configurations, see Backing Up Current Firmware and Hardware Configurations.

Typically, you set the boot mode only once, before you install an operating system (OS) on the server. If you change the boot mode after you have installed an OS, the OS will not boot. Review the OS installation guide to determine whether the OS you intend to install supports UEFI Boot Mode.

The advantages of UEFI Boot Mode include:

  • Faster boot time.

  • No legacy option ROM address constraints.

  • Support for operating system boot partitions greater than 2 terabytes (2 TB). For more information about limitations for supported operating systems, refer to your server product notes.

  • PCIe device configuration utilities are integrated with the BIOS Setup Utility.

  • Bootable operating system images are displayed in the boot list as labeled entities. For example, it displays Windows boot manager labels instead of raw device labels.

  • Efficient power and system management.

  • Robust reliability and fault management.

  • UEFI drivers.

However, you should choose Legacy BIOS Boot Mode in the following situations:

  • The operating system you intend to install does not support booting in UEFI Boot Mode.

  • The boot devices on the server contain legacy option ROMs that must be loaded.

To view or modify the boot mode, see Viewing or Modifying the Current Boot Mode.