Copyright (c) 2017-2018 Netflix, Inc.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.
.Dd December 17, 2023 .Dt EFIBOOTMGR 8 .Os .Sh NAME .Nm efibootmgr .Nd manipulate the EFI Boot Manager .Sh SYNOPSIS .Nm .Op Fl v .Nm .Fl a .Fl b Ar bootnum .Nm .Fl A .Fl b Ar bootnum .Nm .Fl B .Fl b Ar bootnum .Nm .Fl c .Fl l Ar loader .Op Fl aD .Op Fl b Ar bootnum .Op Fl k Ar kernel .Op Fl L Ar label .Op Fl e Ar env .Nm .Fl E .Op Fl d .Op Fl p .Nm .Fl F .Nm .Fl f .Nm .Fl n .Fl b Ar bootnum .Nm .Fl N .Nm .Fl o Ar bootorder .Nm .Fl t Ar timeout .Nm .Fl T .Nm Fl u Ar unix-path .Sh "DESCRIPTION" The .Nm program manipulates how UEFI Boot Managers boot the system. It can create and destroy methods for booting along with activating or deactivating them. It can also change the defined order of boot methods. It can create a temporary boot (BootNext) variable that references a boot method to be tried once upon the next boot.
p The UEFI standard defines how hosts may control what is used to bootstrap the system. Each method is encapsulated within a persistent UEFI variable, stored by the UEFI BIOS of the form .Cm Boot Ns Em XXXX (where XXXX are uppercase hexadecimal digits). These variables are numbered, each describing where to load the bootstrap program from, and whether or not the method is active (used for booting, otherwise the method will be skipped). The order of these methods is controlled by another variable, .Cm BootOrder . The currently booted method is communicated using .Cm BootCurrent . A global timeout can also be set.
p .Nm requires that the kernel module .Xr efirt 9 module be present or loaded to get and set these non-volatile variables.
p The following options are available: l -tag -width Ds t Fl a -activate Activate the given .Ar bootnum boot entry, or the new entry when used with .Fl c . t Fl A -deactivate Deactivate the given .Ar bootnum boot entry. t Fl b -bootnum Ar bootnum When creating or modifying an entry, use .Ar bootnum as the index. When creating a new entry, fail if it already exists. For convenience, if .Ar bootnum is prefixed with .Dq boot , that prefix is ignored. t Fl B -delete Delete the given .Ar bootnum boot entry. t Fl c -create Create a new .Cm Boot variable (aka method or entry). t Fl D -dry-run Process but do not change any variables. t Fl e -env When creating a .Cm Boot variable, include a set of environment variables for the loader to set after parsing the command line. Variables are of the form .Dq a=b and separated by spaces. The argument should be quoted. .Nm appends these to the end of the .Cm Boot environment variable. Before processing anything else, .Xr loader.efi 8 will parse this area and set all variables found there. t Fl E -esp Print the .Fx path to the ESP device, derived from the EFI variables .Va BootCurrent and .Va BootXXXX . This is the ESP partition used by UEFI to boot the current instance of the system. If .Fl d -device-path is specified, the UEFI device path to the ESP is reported instead. If .Fl p -unix-path is specified, the mount point of the ESP is reported instead. t Fl f -fw-ui , Fl F -no-fw-ui Set or clear the request to the system firmware to stop in its user interface on the next boot. t Fl k -kernel Ar kernel The path to and name of the kernel. t Fl l -loader Ar loader The path to and name of the loader. t Fl L -label Ar label An optional description for the method. t Fl n -bootnext Set .Ar bootnum boot entry as the .Cm BootNext variable. t Fl N -delete-bootnext Delete the .Cm BootNext optional variable. t Fl o -bootorder Ar bootorder Set .Cm BootOrder variable to the given comma delimited set of .Ar bootnum Ns s . The numbers are in hex to match .Cm Boot Ns Em XXXX , but may omit leading zeros. t Fl t -set-timeout Ar timeout Set the bootmenu timeout value. t Fl T -del-timeout Delete the .Cm BootTimeout variable. t Fl u -efidev Ar unix-path Displays the UEFI device path of .Ar unix-path . t Fl v -verbose Display the device path of boot entries in the output. .El .Sh Examples To display the current .Cm Boot related variables in the system:
p .Dl efibootmgr -v
p This will display the optional .Cm BootNext (if present), .Cm BootCurrent (currently booted method), followed by the optional .Cm Timeout value, any .Cm BootOrder that may be set, followed finally by all currently defined .Cm Boot variables, active or not. The verbose flag,
q Fl v , augments this output with the disk partition uuids, size/offset and device-path of the variable. The flag will also include any unreferenced (by BootOrder) variables.
p The .Nm program can be used to create new EFI boot variables. The following command may be used to create a new boot method, using the EFI partition mounted under
a /boot/efi , mark the method active, using the given loader and label the method .Qq FreeBSD-15 :
p .Dl efibootmgr -a -c -l /boot/efi/EFI/freebsd/loader.efi -L FreeBSD-15
p This will result in the next available bootnum being assigned to a new UEFI boot variable, and given the label .Qq FreeBSD-15 such as:
p .Dl Boot0009 FreeBSD-15
p Note newly created boot entries are, by default, created inactive, hence the reason .Fl a flag is specified above so that it will be considered for booting. The active state is denoted by a '*' following the .Cm Boot Ns Em XXXX name in the output. They are also inserted into the first position of current .Cm BootOrder variable if it exists. They must first be set to active before being considered available to attempt booting from, else they are ignored.
p .Dl efibootmgr -B -b 0009
p Will delete the given boot entry Boot0009.
p To set the given boot entry active:
p .Dl efibootmgr -a -b 0009
p To set a given boot entry to be used as the .Cm BootNext variable, irrespective of its active state, use:
p .Dl efibootmgr -n -b 0009
p To set the .Cm BootOrder for the next reboot use:
p .Dl efibootmgr -o 0009,0003,... .Sh SEE ALSO .Xr efirt 9 , .Xr efivar 8 , .Xr gpart 8 , .Xr uefi 8 .Sh STANDARDS The Unified Extensible Firmware Interface Specification is available from
a www.uefi.org .