efibootmgr Man page

EFIBOOTMGR(8) EFIBOOTMGR(8)

NAME

efibootmgr – manipulate the EFI Boot Manager

SYNOPSIS

efibootmgr [ -a ] [ -A ] [ -b XXXX ] [ -B XXXX ] [ -c ] [ -d DISK ] [
-D ] [ -e 1|3|-1 ] [ -E NUM ] [ -g ] [ -H XXXX ] [ -i NAME ] [ -l

NAME

] [ -L LABEL ] [ -n XXXX ] [ -N ] [ -o XXXX,YYYY,ZZZZ … ] [ -O ] [ -p
PART ] [ -q ] [ -t seconds ] [ -T ] [ -u ] [ -U XXXX ] [ -v ] [ -V ] [
-w ] [ -@ file ]

DESCRIPTION

efibootmgr is a userspace application used to modify the Intel Extensi‐
ble Firmware Interface (EFI) Boot Manager. This application can create
and destroy boot entries, change the boot order, change the next run‐
ning boot option, and more.

Details on the EFI Boot Manager are available from the EFI Specifica‐
tion, v1.02 or later, available from:

Note: efibootmgr requires that the kernel support access to EFI
non-volatile variables through /sys/firmware/efi/vars or
/sys/firmware/efi/efivars/.

OPTIONS

The following is a list of options accepted by efibootmgr:

-a | –active
Sets bootnum active

-A | –inactive
Sets bootnum inactive

-b | –bootnum XXXX
Modify BootXXXX (hex)

-B | –delete-bootnum
Delete bootnum (hex)

-c | –create
Create new variable bootnum and add to bootorder

-d | –disk DISK
The disk containing the loader (defaults to /dev/sda)

-D | –remove-dups
Remove duplicated entries from BootOrder

-e | –edd30 1|3|-1
Force EDD 1.0 or 3.0 creation variables, or guess.

-E | –edd-device NUM
EDD 1.0 device number (defaults to 0x80)

-g | –gpt
Force disk with invalid PMBR to be treated as GPT

-i | –iface

NAME

create a netboot entry for the named interface

-l | –loader

NAME

Specify a loader (defaults to \\elilo.efi)

-L | –label LABEL
Boot manager display label (defaults to “Linux”)

-n | –bootnext XXXX
Set BootNext to XXXX (hex)

-N | –delete-bootnext
Delete BootNext

-o | –bootorder XXXX,YYYY,ZZZZ
Explicitly set BootOrder (hex). Any value from 0 to FFFF is
accepted so long as it corresponds to an existing Boot#### vari‐
able, and zero padding is not required.

-O | –delete-bootorder
Delete BootOrder

-p | –part PART
Partition number containing the bootloader (defaults to 1)

-q | –quiet
Quiet mode – supresses output.

-t | –timeout seconds
Boot Manager timeout, in seconds.

-T | –delete-timeout
Delete Timeout variable.

-u | –unicode | –UCS-2
pass extra command line arguments as UCS-2 (default is ASCII)

-v | –verbose
Verbose mode – prints additional information

-V | –version
Just print version string and exit.

-w | –write-signature
write unique signature to the MBR if needed

-@ | –append-binary-args
append extra variable args from file (use – to read from stdin).
Data in file is appended as command line arguments to the boot
loader command, with no modification to the data, so you can
pass any binary or text data necessary.

EXAMPLES
1.

DISPLAYING THE CURRENT SETTINGS (MUST BE ROOT).
[root@localhost ~]# efibootmgr
BootCurrent: 0004
BootNext: 0003
BootOrder: 0004,0000,0001,0002,0003
Timeout: 30 seconds
Boot0000* Diskette Drive(device:0)
Boot0001* CD-ROM Drive(device:FF)
Boot0002* Hard Drive(Device:80)/HD(Part1,Sig00112233)
Boot0003* PXE Boot: MAC(00D0B7C15D91)
Boot0004* Linux

This shows:

· BootCurrent – the boot entry used to start the currently run‐
ning system

· BootOrder – the boot order as would appear in the boot man‐
ager. The boot manager tries to boot the first active entry
in this list. If unsuccessful, it tries the next entry, and
so on.

· BootNext – the boot entry which is scheduled to be run on next
boot. This supercedes BootOrder for one boot only, and is
deleted by the boot manager after first use. This allows you
to change the next boot behavior without changing BootOrder.

· Timeout – the time in seconds between when the boot manager
appears on the screen until when it automatically chooses the
startup value from BootNext or BootOrder.

· Five boot entries (0000 – 0004), along with the active/inac‐
tive flag (* means active) and the name displayed on the
screen.

2.

CREATING A NEW BOOT OPTION
An OS installer would call efibootmgr -c. This assumes that /boot/efi
is your EFI System Partition, and is mounted at /dev/sda1. This cre‐
ates a new boot option, called “Linux”, and puts it at the top of the
boot order list. Options may be passed to modify the default behavior.
The default OS Loader is elilo.efi.

3.

CHANGING THE BOOT ORDER
Assuming the configuration in Example #1, efibootmgr -o 3,4 could be
called to specify PXE boot first, then Linux boot.

4.

CHANGING THE BOOT ORDER FOR THE NEXT BOOT ONLY
Assuming the configuration in Example #1, efibootmgr -n 4 could be
called to specify that the Linux entry be taken on next boot.

5.

DELETING A BOOT OPTION
Assuming the configuration in Example #1, efibootmgr -b 4 -B could be
called to delete entry 4 and remove it from the BootOrder.

6.

CREATING NETWORK BOOT ENTRIES
A system administrator wants to create a boot option to network boot.
You create the boot entry with: efibootmgr -c -i eth0 -L netboot [ -l
‘\filename.efi’ ]

BUGS

Please direct any bugs, features, patches, etc. to Peter Jones:
https://github.com/rhinstaller/efibootmgr .

AUTHOR

This man page was generated by dann frazier for the
Debian GNU/Linux operating system, but may be used by others.

SEE ALSO

elilo(1)

11 January 2012 EFIBOOTMGR(8)

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