UEFI

UEFI, expanded as Unified Extensible Firmware Interface, defines the software interface between an OS and its platform firmware. Generally, UEFI replaces the BIOS firmware interface. It enables remote diagnostics and facilitates the repair of computers even when an OS is not present. Furthermore, booting legacy BIOS-based systems from GPT disks is also possible, and such a boot scheme is commonly called BIOS-GPT.