efibootmgr - manipulate the UEFI Boot Manager
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 ]
efibootmgr is a userspace application used to modify the UEFI 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 UEFI Boot Manager are available from the UEFI Specification,
v1.02 or later, available from: http://www.uefi.org
Note: efibootmgr requires that the
kernel support access to EFI non-volatile variables through
/sys/firmware/efi/vars or /sys/firmware/efi/efivars/.
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.
[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
Each of the above are boot variables, which are defined as follows:
- •
- 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.
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.
Assuming the configuration in the first example,
efibootmgr -o 3,4 could
be called to specify PXE boot first, then Linux boot.
Assuming the configuration in the first example,
efibootmgr -n 4 could be
called to specify that the Linux entry be taken on next boot.
Assuming the configuration in the first example,
efibootmgr -b 4 -B could
be called to delete entry 4 and remove it from the BootOrder.
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'
]
Please direct any bugs, features, patches, etc. to the Red Hat bootloader team
at https://github.com/rhboot/efibootmgr .
This man page was generated by dann frazier <dannf@debian.org> for the
Debian GNU/Linux operating system and updated by Robert Bisewski
<contact@ibiscybernetics.com>, but may be used by others.
elilo(1)