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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 arm64 and ia64.
44 boot process loads system bootstrap code located in an EFI System Partition
46 The ESP is a GPT or MBR partition with a specific identifier that contains an
48 FAT file system with a specified file hierarchy.
49 .Bl -column -offset indent ".Sy Partition Scheme" ".Sy ESP Identifier"
50 .It Sy "Partition Scheme" Ta Sy "ESP Identifier"
51 .It GPT Ta C12A7328-F81F-11D2-BA4B-00A0C93EC93B
57 boot process proceeds as follows:
58 .Bl -enum -offset indent -compact
61 firmware runs at power up and searches for an OS loader in the EFI system
63 The path to the loader may be set by an EFI environment variable.
64 If not set, the default is
65 .Pa /EFI/BOOT/BOOTX64.EFI .
68 boot configuration for
73 .Pa /EFI/BOOT/BOOTX64.EFI .
76 reads boot configuration from
80 Unlike other first-stage boot loaders,
82 passes the configuration to the next stage boot loader and does not
83 itself act on the contents of the file.
86 searches partitions of type
92 The search begins with partitions on the device from which
94 was loaded, and continues with other available partitions.
96 then loads and executes
100 loads and boots the kernel, as described in
106 system console is automatically selected when booting via
109 .Bl -tag -width /boot/loader -compact
110 .It Pa /boot/boot1.efi
114 .It Pa /boot/boot1.efifat
116 FAT file system image containing
124 .It Pa /boot/loader.efi
125 Final stage bootstrap
126 .It Pa /boot/kernel/kernel
128 .It Pa /boot/kernel.old/kernel
129 typical non-default kernel (optional)
140 boot support first appeared in
145 boot support was developed by
146 .An Benno Rice Aq Mt benno@FreeBSD.org ,
147 .An Ed Maste Aq Mt emaste@FreeBSD.org ,
149 .An Nathan Whitehorn Aq Mt nwhitehorn@FreeBSD.org .
152 Foundation sponsored portions of the work.
154 EFI environment variables are not supported by