efibootmgr(8)

1EFIBOOTMGR(8)                                                    EFIBOOTMGR(8)
2
3
4

NAME

6       efibootmgr - manipulate the UEFI Boot Manager
7

SYNOPSIS

9       efibootmgr  [  -a  ]  [ -A ] [ -b XXXX ] [ -r | -y ] [ -B ] [ -c ] [ -d
10       DISK ] [ -D ] [ -e 1|3|-1 ] [ -E NUM ] [ -g ] [ -i NAME ] [ -l NAME ] [
11       -L  LABEL  ] [ -m t|f ] [ -M X ] [ -n XXXX ] [ -N ] [ -o XXXX,YYYY,ZZZZ
12       ... ] [ -O ] [ -p PART ] [ -q ] [ -t seconds ] [ -T ] [ -u ] [ -v  ]  [
13       -V ] [ -w ] [ -@ file ]
14
15

DESCRIPTION

17       efibootmgr is a userspace application used to modify the UEFI Boot Man‐
18       ager. This application can create and destroy boot entries, change  the
19       boot order, change the next running boot option, and more.
20
21       Details on the UEFI Boot Manager are available from the UEFI Specifica‐
22       tion, v1.02 or later, available from: http://www.uefi.org
23
24              Note: efibootmgr requires that the kernel support access to  EFI
25              non-volatile   variables   through   /sys/firmware/efi/vars   or
26              /sys/firmware/efi/efivars/.
27

OPTIONS

29       The following is a list of options accepted by efibootmgr:
30
31       -a | --active
32              Sets bootnum active
33
34       -A | --inactive
35              Sets bootnum inactive
36
37       -b | --bootnum XXXX
38              Modify BootXXXX (hex)
39
40       -B | --delete-bootnum
41              Delete bootnum
42
43       -c | --create
44              Create new variable bootnum and add to bootorder
45
46       -d | --disk DISK
47              The disk containing the loader (defaults to /dev/sda)
48
49       -D | --remove-dups
50              Remove duplicated entries from BootOrder
51
52       -e | --edd30 1|3|-1
53              Force EDD 1.0 or 3.0 creation variables, or guess.
54
55       -E | --edd-device NUM
56              EDD 1.0 device number (defaults to 0x80)
57
58       -g | --gpt
59              Force disk with invalid PMBR to be treated as GPT
60
61       -i | --iface NAME
62              create a netboot entry for the named interface
63
64       -l | --loader NAME
65              Specify a loader (defaults to \\elilo.efi)
66
67       -L | --label LABEL
68              Boot manager display label (defaults to "Linux")
69
70       -m | --mirror-below-4G t|f
71              Set t if you want to mirror memory below 4GB
72
73       -M | --mirror-above-4G X
74              X percentage memory to mirror above  4GB.  Floating-point  value
75              with up to 2 decimal places is accepted.
76
77       -n | --bootnext XXXX
78              Set BootNext to XXXX (hex)
79
80       -N | --delete-bootnext
81              Delete BootNext
82
83       -o | --bootorder XXXX,YYYY,ZZZZ
84              Explicitly  set  BootOrder  (hex).  Any  value from 0 to FFFF is
85              accepted so long as it corresponds to an existing Boot#### vari‐
86              able, and zero padding is not required.
87
88       -O | --delete-bootorder
89              Delete BootOrder
90
91       -p | --part PART
92              Partition number containing the bootloader (defaults to 1)
93
94       -q | --quiet
95              Quiet mode - supresses output.
96
97       -r | --driver
98              Operate on Driver#### variables instead of Boot#### variables.
99
100       -t | --timeout seconds
101              Boot Manager timeout, in seconds.
102
103       -T | --delete-timeout
104              Delete Timeout variable.
105
106       -u | --unicode | --UCS-2
107              Handle extra command line arguments as UCS-2 (default is ASCII)
108
109       -v | --verbose
110              Verbose mode - prints additional information
111
112       -V | --version
113              Just print version string and exit.
114
115       -w | --write-signature
116              write unique signature to the MBR if needed
117
118       -y | --sysprep
119              Operate on SysPrep#### variables instead of Boot#### variables.
120
121       -@ | --append-binary-args
122              append extra variable args from file (use - to read from stdin).
123              Data in file is appended as command line arguments to  the  boot
124              loader  command,  with  no  modification to the data, so you can
125              pass any binary or text data necessary.
126

EXAMPLES

128
129
130   Displaying the current settings (must be root):
131
132       [root@localhost ~]# efibootmgr
133       BootCurrent: 0004
134       BootNext: 0003
135       BootOrder: 0004,0000,0001,0002,0003
136       Timeout: 30 seconds
137       Boot0000* Diskette Drive(device:0)
138       Boot0001* CD-ROM Drive(device:FF)
139       Boot0002* Hard Drive(Device:80)/HD(Part1,Sig00112233)
140       Boot0003* PXE Boot: MAC(00D0B7C15D91)
141       Boot0004* Linux
142
143       Each of the above are boot variables, which are defined as follows:
144
145              · BootCurrent - the boot entry used to start the currently  run‐
146                ning system
147
148              · BootOrder  -  the  boot order as would appear in the boot man‐
149                ager.  The boot manager tries to boot the first  active  entry
150                in this list. If unsuccessful, it tries the next entry, and so
151                on.
152
153              · BootNext - the boot entry which is scheduled to be run on next
154                boot.  This  supercedes  BootOrder  for  one boot only, and is
155                deleted by the boot manager after first use. This  allows  you
156                to change the next boot behavior without changing BootOrder.
157
158              · Timeout  -  the  time in seconds between when the boot manager
159                appears on the screen until when it automatically chooses  the
160                startup value from BootNext or BootOrder.
161
162              · Five  boot  entries (0000 - 0004), along with the active/inac‐
163                tive flag (* means active)  and  the  name  displayed  on  the
164                screen.
165
166   Creating a new boot option
167       An  OS installer would call efibootmgr -c.  This assumes that /boot/efi
168       is your EFI System Partition, and is mounted at /dev/sda1. This creates
169       a  new  boot option, called "Linux", and puts it at the top of the boot
170       order list. Options may be passed to modify the default  behavior.  The
171       default OS Loader is elilo.efi.
172
173   Changing the boot order
174       Assuming  the  configuration  in  the  first example, efibootmgr -o 3,4
175       could be called to specify PXE boot first, then Linux boot.
176
177   Changing the boot order for the next boot only
178       Assuming the configuration in the first example, efibootmgr -n 4  could
179       be called to specify that the Linux entry be taken on next boot.
180
181   Deleting a boot option
182       Assuming  the  configuration  in  the first example, efibootmgr -b 4 -B
183       could be called to delete entry 4 and remove it from the BootOrder.
184
185   Creating network boot entries
186       A system administrator wants to create a boot option to  network  boot.
187       You  create  the boot entry with: efibootmgr -c -i eth0 -L netboot [ -l
188       '\filename.efi' ]
189

BUGS

191       Please direct any bugs, features, patches, etc. to the  Red  Hat  boot‐
192       loader team at https://github.com/rhboot/efibootmgr .
193

AUTHOR

195       This  man page was generated by dann frazier <dannf@debian.org> for the
196       Debian GNU/Linux operating system and updated by Robert Bisewski  <con‐
197       tact@ibiscybernetics.com>, but may be used by others.
198