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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 locates the first partition with the type
82 loads and boots the kernel, as described in
88 system console is automatically selected when booting via
91 .Bl -tag -width /boot/loader -compact
92 .It Pa /boot/boot1.efi
96 .It Pa /boot/boot1.efifat
98 FAT file system image containing
106 .It Pa /boot/loader.efi
107 Final stage bootstrap
108 .It Pa /boot/kernel/kernel
110 .It Pa /boot/kernel.old/kernel
111 typical non-default kernel (optional)
120 boot support first appeared in
125 boot support was developed by
126 .An Benno Rice Aq Mt benno@FreeBSD.org ,
127 .An Ed Maste Aq Mt emaste@FreeBSD.org ,
129 .An Nathan Whitehorn Aq Mt nwhitehorn@FreeBSD.org .
132 Foundation sponsored portions of the work.
134 EFI environment variables are not supported by
141 from the first FreeBSD-UFS file system it locates, even if it is on a
152 does not support a typical root file system on ZFS configuration.