Ubuntu Manpage: efibootmgr - manipulate the EFI Boot Manager

NAME

       efibootmgr - manipulate the EFI Boot Manager

SYNOPSIS

       efibootmgr  [  -a  ]  [ -A ] [ -b XXXX ] [ -r | -y ] [ -B ] [ -c ] [ -d DISK ] [ -D ] [ -e
       1|3|-1 ] [ -E NUM ] [ -g ] [ -i NAME ] [ -l NAME ] [ -L LABEL ] [ -m t|f ] [ -M X ]  [  -n
       XXXX  ] [ -N ] [ -o XXXX,YYYY,ZZZZ ... ] [ -O ] [ -p PART ] [ -q ] [ -t seconds ] [ -T ] [
       -u ] [ -v ] [ -V ] [ -w ] [ -@ file ]

DESCRIPTION

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

       Details on the EFI Boot Manager are available from the EFI Specification, v1.02 or  later,
       available from:
        <URL:http://developer.intel.com>

              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

       -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")

       -m | --mirror-below-4G t|f
              Set t if you want to mirror memory below 4GB

       -M | --mirror-above-4G X
              X percentage memory to mirror above 4GB. Floating-point value with up to 2  decimal
              places is accepted.

       -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#### variable, 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.

       -r | --driver
              Operate on Driver#### variables instead of Boot#### variables.

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

       -T | --delete-timeout
              Delete Timeout variable.

       -u | --unicode | --UCS-2
              Handle 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

       -y | --sysprep
              Operate on SysPrep#### variables instead of Boot#### variables.

       -@ | --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

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 running system

• BootOrder - the boot order as would appear in the boot manager. 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/inactive flag (* means
active) and the name displayed on the screen.

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 creates 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.

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.

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.

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.

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 <dannf@debian.org> for the Debian GNU/Linux
       operating system, but may be used by others.