systemd-boot
Related articles
systemd-boot (previously called gummiboot), is a simple UEFI boot manager which executes configured EFI images. The default entry is selected by a configured pattern (glob) or an on-screen menu. It is included with systemd since systemd 220-2.
It is simple to configure, but can only start EFI executables, such as the Linux kernel EFISTUB, UEFI Shell, GRUB, the Windows Boot Manager, and such.
Installation
EFI boot
- Make sure you are booted in UEFI mode.
- Verify your EFI variables are accessible.
- Mount your EFI System Partition(ESP) properly.
$esp
is used to denote the mountpoint in this article. - Copy your kernel and initramfs onto that ESP.
- Finally, Type the following command to install systemd-boot:
# bootctl --path=$esp install
It will copy the systemd-boot binary to your EFI System Partition ($esp/EFI/systemd/systemd-bootx64.efi
and$esp/EFI/Boot/BOOTX64.EFI
- both of which are identical - on x64 systems) and add systemd-boot itself as the default EFI application (default boot entry) loaded by the EFI Boot Manager.
Legacy boot
You can also successfully install systemd-boot if booted with a legacy OS. However, this requires that you later on tell your firmware to launch systemd-boot's EFI file on boot:
- you either have a working EFI shell somewhere;
- or your firmware interface provides you with a way of properly setting the EFI file that will be loaded at boot time.
If you can do so, the installation is easier: go into your EFI shell or your firmware configuration interface, and change your machine's default EFI file to $esp/EFI/systemd/systemd-bootx64.efi
(systemd-bootia32.efi
on i686 systems).
Updating
systemd-boot (bootctl(1), systemd-efi-boot-generator(8)) assumes that your EFI System Partition is mounted on /boot
. Unlike the previous separate gummiboot package, which updated automatically on a new package release with a post_install
script, updates of new systemd-boot versions are now handled manually by the user:
# bootctl update
If the ESP is not mounted on /boot
, the --path=
option can pass it. For example:
# bootctl --path=/boot/$esp update
Configuration
Basic configuration
The basic configuration is kept in $esp/loader/loader.conf
, with three possible configuration options:
-
default
– default entry to select (without the.conf
suffix); can be a wildcard likearch-*
-
timeout
– menu timeout in seconds. If this is not set, the menu will only be shown when you hold the space key while booting.
-
editor
- whether to enable the kernel parameters editor or not.1
(default) is to enable,0
is to disable. Since the user can addinit=/bin/bash
to bypass root password and gain root access, it's strongly recommended to set this option to0
.
Example:
$esp/loader/loader.conf
default arch timeout 4 editor 0
Note that the first 2 options can be changed in the boot menu itself, which will store them as EFI variables.
Adding boot entries
bootctl searches for boot menu items in $esp/loader/entries/*.conf
– each file found must contain exactly one boot entry. The possible options are:
-
title
– operating system name. Required.
-
version
– kernel version, shown only when multiple entries with same title exist. Optional.
-
machine-id
– machine identifier from/etc/machine-id
, shown only when multiple entries with same title and version exist. Optional.
-
efi
– EFI program to start, relative to your ESP ($esp
); e.g./vmlinuz-linux
. Either this orlinux
(see below) is required.
-
options
– command line options to pass to the EFI program or Kernel Boot Parameters. Optional, but you will need at leastinitrd=efipath
androot=dev
if booting Linux.
For Linux, you can specify linux path-to-vmlinuz
and initrd path-to-initramfs
; this will be automatically translated to efi path
and options initrd=path
– this syntax is only supported for convenience and has no differences in function.
Standard root installations
Here is an example entry for a root partition without LVM or LUKS:
$esp/loader/entries/arch.conf
title Arch Linux linux /vmlinuz-linux initrd /initramfs-linux.img options root=PARTUUID=14420948-2cea-4de7-b042-40f67c618660 rw
Please note in the example above that PARTUUID/PARTLABEL identifies a GPT partition, and differs from UUID/LABEL, which identifies a filesystem. Using the PARTUUID/PARTLABEL is advantageous because it is invariant (i.e. unchanging) if you reformat the partition with another filesystem, or if the /dev/sd* mapping changed for some reason. It is also useful if you do not have a filesystem on the partition (or use LUKS, which does not support LABELs).
LVM root installations
Here is an example for a root partition using Logical Volume Management:
$esp/loader/entries/arch-lvm.conf
title Arch Linux (LVM) linux /vmlinuz-linux initrd /initramfs-linux.img options root=/dev/mapper/<VolumeGroup-LogicalVolume> rw
Replace <VolumeGroup-LogicalVolume>
with the actual VG and LV names (e.g. root=/dev/mapper/volgroup00-lvolroot
). Alternatively, it is also possible to use a UUID instead:
.... options root=UUID=<UUID identifier> rw
Note that root=UUID=
is used instead of root=PARTUUID=
, which is used for Root partitions without LVM or LUKS.
Encrypted Root Installations
Here is an example configuration file for an encrypted root partition (DM-Crypt / LUKS):
$esp/loader/entries/arch-encrypted.conf
title Arch Linux Encrypted linux /vmlinuz-linux initrd /initramfs-linux.img options cryptdevice=UUID=<UUID>:<mapped-name> root=/dev/mapper/<mapped-name> quiet rw
UUID is used in this example; PARTUUID should be able to replace the UUID, if so desired. You may also replace the /dev path with a regular UUID. See Dm-crypt/System configuration#Boot loader.
You can also add other EFI programs such as \EFI\arch\grub.efi
.
btrfs subvolume root installations
If booting a btrfs subvolume as root, amend the options
line with rootflags=subvol=<root subvolume>
. In the example below, root has been mounted as a btrfs subvolume called 'ROOT' (e.g. mount -o subvol=ROOT /dev/sdxY /mnt
):
$esp/loader/entries/arch-btrfs-subvol.conf
title Arch Linux linux /vmlinuz-linux initrd /initramfs-linux.img options root=PARTUUID=14420948-2cea-4de7-b042-40f67c618660 rw rootflags=subvol=ROOT
A failure to do so will otherwise result in the following error message: ERROR: Root device mounted successfully, but /sbin/init does not exist.
EFI Shells or other EFI apps
In case you installed EFI shells and other EFI application into the ESP, you can use the following snippets:
$esp/loader/entries/uefi-shell-v1-x86_64.conf
title UEFI Shell x86_64 v1 efi /EFI/shellx64_v1.efi
$esp/loader/entries/uefi-shell-v2-x86_64.conf
title UEFI Shell x86_64 v2 efi /EFI/shellx64_v2.efi
Support hibernation
The following keys are used inside the menu:
-
Up/Down
- select entry -
Enter
- boot the selected entry -
d
- select the default entry to boot (stored in a non-volatile EFI variable) -
-/T
- decrease the timeout (stored in a non-volatile EFI variable) -
+/t
- increase the timeout (stored in a non-volatile EFI variable) -
e
- edit the kernel command line. has no effect if theeditor
config option is set to0
. -
v
- show the gummiboot and UEFI version -
Q
- quit -
P
- print the current configuration -
h/?
- help
These hotkeys will, when pressed inside the menu or during bootup, directly boot a specific entry:
-
l
- Linux -
w
- Windows -
a
- OS X -
s
- EFI Shell -
1-9
- number of entry
Troubleshooting
Manual entry using efibootmgr
If bootctl install
command failed, you can create a EFI boot entry manually using efibootmgr:
# efibootmgr -c -d /dev/sdX -p Y -l /EFI/systemd/systemd-bootx64.efi -L "Linux Boot Manager"
where /dev/sdXY
is the EFI System Partition.
Menu does not appear after Windows upgrade
For example, if you upgraded from Windows 8 to Windows 8.1, and you no longer see a boot menu after the upgrade (i.e., Windows boots immediately):
- Make sure Secure Boot (UEFI setting) and Fast Startup (Windows power option setting) are both disabled.
- Make sure your UEFI prefers Linux Boot Manager over Windows Boot Manager (UEFI setting like Hard Drive Disk Priority).
To make Windows 8.X and above respect your boot order, you must enter a Windows group policy and have it execute a batch (.bat) file on startup. In Windows:
- Open a command prompt with admin privlages. Type in
bcdedit /enum firmware
- Find the Firmware Application that has "Linux" in the description, e.g. "Linux Boot Manager"
- Copy the Identifier, including the brackets, e.g.
{31d0d5f4-22ad-11e5-b30b-806e6f6e6963}
- Create a batch file (e.g.
bootorder.bat
) somewhere on your system with the following contents:bcdedit /set {fwbootmgr} DEFAULT {identifier_copied_in_step_3}
(e.g.bcdedit /set {fwbootmgr} DEFAULT {31d0d5f4-22ad-11e5-b30b-806e6f6e6963}
). - Open gpedit and under Local Computer Policy > Computer Configuration > Windows Settings > Scripts(Startup/Shutdown), choose Startup. That should open a window named Startup Properties.
- Under the Scripts tab, choose the Add button
- Click Browse and select the batch file you created in step 4.
Alternatively, you can make the default Windows boot loader load systemd-boot instead. In an administrator command prompt in Windows, one can change this entry as follows:
bcdedit /set {bootmgr} path \EFI\systemd\systemd-bootx64.efi