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This is efibootmgr, a Linux user-space application 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 above, available from http://www.uefi.org.
Note: efibootmgr requires that the kernel module efivars be loaded
prior to use. 'modprobe efivars' should do the trick.
usage: efibootmgr [options]
-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 (defaults to /dev/sda) containing loader
-e | --edd [1|3|-1] force EDD 1.0 or 3.0 creation variables, or guess
-E | --device num EDD 1.0 device number (defaults to 0x80)
-g | --gpt force disk w/ invalid PMBR to be treated as GPT
-i | --iface name create a netboot entry for the named interface
-l | --loader name (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)
-O | --delete-bootorder delete BootOrder
-p | --part part (defaults to 1) containing loader
-q | --quiet be quiet
-t | --timeout seconds Boot manager timeout
-T | --delete-timeout delete Timeout value
-u | --unicode | --UCS-2 pass extra args as UCS-2 (default is ASCII)
-v | --verbose print additional information
-V | --version return version and exit
-w | --write-signature write unique sig to MBR if needed
-@ | --append-binary-args append extra variable args from
file (use - to read from stdin).
Typical usage:
1) Root can use it to display the current Boot Manager settings.
[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 on 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 superceeds 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), the active/inactive flag (* means
active), and the name displayed on the screen.
2) 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.
3) A system administrator wants to change the boot order. She would
call 'efibootmgr -o 3,4' to specify PXE boot first, then Linux
boot.
4) A system administrator wants to change the boot order for the next
boot only. She would call 'efibootmgr -n 4' to specify that the
Linux entry be taken on next boot.
5) A system administrator wants to delete the Linux boot option from
the menu. 'efibootmgr -b 4 -B' deletes entry 4 and removes it
from BootOrder.
6) A system administrator wants to create a boot option to network
boot (PXE). You create the boot entry with:
'efibootmgr -c -i eth0 -L netboot'
Many other uses may be found.
Please direct any bugs, features, patches, etc. to Peter Jones,
https://github.com/rhinstaller/efibootmgr .
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