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32 .Nd Unified Extensible Firmware Interface bootstrapping procedures
36 Unified Extensible Firmware Interface provides boot- and run-time services
39 is a replacement for the legacy BIOS on the i386 and amd64 CPU architectures,
40 and is also used on arm, arm64 and ia64.
42 The UEFI specification is the successor to the Extensible Firmware Interface
44 The terms are often used interchangeably.
48 boot process loads system bootstrap code located in an EFI System Partition
50 The ESP is a GPT or MBR partition with a specific identifier that contains an
52 FAT file system with a specified file hierarchy.
53 .Bl -column -offset indent ".Sy Partition Scheme" ".Sy ESP Identifier"
54 .It Sy "Partition Scheme" Ta Sy "ESP Identifier"
55 .It GPT Ta C12A7328-F81F-11D2-BA4B-00A0C93EC93B
61 boot process proceeds as follows:
62 .Bl -enum -offset indent -compact
65 firmware runs at power up and searches for an OS loader in the EFI system
67 The path to the loader may be set by an EFI environment variable.
68 If not set, an architecture-specific default is used.
69 .Bl -column -offset indent "Architecture" "Default Path"
70 .It Sy Architecture Ta Sy Default Path
71 .It amd64 Ta Pa /EFI/BOOT/BOOTX64.EFI
72 .It arm64 Ta Pa /EFI/BOOT/BOOTAA64.EFI
77 boot configuration for
84 reads boot configuration from
90 searches partitions of type
96 The search begins with partitions on the device from which
98 was loaded, and continues with other available partitions.
103 partitions exist on the same device the
105 partition is preferred.
108 loads and boots the kernel, as described in
114 system console is automatically selected when booting via
117 .Bl -tag -width /boot/loader -compact
120 .It Pa /boot/loader.efi
121 Final stage bootstrap
122 .It Pa /boot/kernel/kernel
124 .It Pa /boot/kernel.old/kernel
125 typical non-default kernel (optional)
138 EFI boot support for the ia64 architecture first appeared in
141 boot support for amd64 first appeared in
146 EFI environment variables are not supported by