Editing UEFI

{{welcome}}

==Introduction==

UEFI -- Unified Extensible	Firmware Interface bootstrapping procedures

==DESCRIPTION==

The UEFI Unified Extensible Firmware Interface provides boot- and runtime services to operating	systems.  UEFI is a replacement	for the	legacy   BIOS on the i386 and amd64	CPU architectures, and is also used on arm,    arm64 and ia64.

The UEFI specification is the successor to	the Extensible Firmware	Interface (EFI)	specification.	The terms are often used interchangeably.

The UEFI boot process loads system	bootstrap code located in an EFI System Partition (ESP).  The ESP is a	GPT or MBR partition with a specific identifier	that contains an msdosfs(5) FAT	file system with a specified   file hierarchy.

{|class="wikitable" style="width:96.5%;background:#FFFFFF; border:2px solid #008000;text-align:left;padding: 10px" 
|-
! scope="col" style="width: 100px;"|'''Partition Scheme'''
! scope="col" style="width: 350px;"|'''ESP Identifier'''
|-
|GPT	||C12A7328-F81F-11D2-BA4B-00A0C93EC93B
|-
|MBR	||0xEF
|}

The UEFI boot process proceeds as follows
1. UEFI firmware runs at power up and searches for	an OS loader in the EFI system partition.  The path to the loader may beset by an EFI environment variable.  If	not set, an architecture-specific default is used.

{|class="wikitable" style="width:96.5%;background:#FFFFFF; border:2px solid #008000;text-align:left;padding: 10px" 
|-
! scope="col" style="width: 100px;"|'''Architecture'''
! scope="col" style="width: 350px;"|'''Default Path'''
|-    
|amd64	||/EFI/BOOT/BOOTX64.EFI
|-
|arm64	|| /EFI/BOOT/BOOTAA64.EFI
|}

The default UEFI boot configuration for	FreeBSD	installs boot1.efi in the default path.
2.  boot1.efi reads	boot configuration from	/boot.config or	/boot/config.  Unlike other first-stage	boot loaders,
boot1.efi passes the configuration to the next stage boot loader and does	not itself act on the contents of the file.
3.  boot1.efi searches partitions of type freebsd-ufs and freebsd-zfs for	loader.efi.  The search	begins with partitions
on the device from which boot1.efi was loaded, and continues with other available partitions.  If both freebsd-ufs and
freebsd-zfs partitions exist on	the same device	the freebsd-zfs partition is preferred.  boot1.efi then loads and
executes loader.efi.
4. loader.efi loads and boots the kernel, as described in loader(8).

The vt(4) system console is automatically selected	when booting via UEFI.

FILES
{|class="wikitable" style="width:96.5%;background:#FFFFFF; border:2px solid #008000;text-align:left;padding: 10px" 
|-
! scope="col" style="width: 100px;"|'''Architecture'''
! scope="col" style="width: 350px;"|'''Default Path'''
|-
|/boot/boot1.efi|| First stage UEFI bootstrap
|-
|/boot/boot1.efifat||msdosfs(5) FAT file system image containing boot1.efi for  use by bsdinstall(8)	and the	bootcode argument to gpart(8).
|-
|/boot/loader.efi||Final stage bootstrap
|-
|/boot/kernel/kernel|| default kernel
|-
|/boot/kernel.old/kernel||typical non-default kernel (optional)
|}











[[Category:Sysutils]]