systemd-boot
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, which is installed on Arch system by default.
It is simple to configure but it can only start EFI executables such as the Linux kernel EFISTUB, UEFI Shell, GRUB, the Windows Boot Manager.
Installation
Installing the EFI boot manager
To install the systemd-boot EFI boot manager, first make sure the system has booted in UEFI mode and that UEFI variables are accessible. This can be checked by running the command efivar --list
.
It should be noted that systemd-boot is only able to load the EFISTUB kernel from the EFI System Partition (ESP). To keep the kernel updated, it is simpler and therefore recommended to mount the ESP to /boot
.
/boot
, make sure to NOT rely on autofs (systemd-gpt-auto-generator) mechanism to mount it, always have it mounted manually or using /etc/fstab prior to the any system or kernel update, otherwise you may not be able to mount it after the update, locking you in the currently running kernel with no ability to update the copy of kernel on ESP and errors like:
systemd[1]: Failed to mount EFI System Partition Automount. kernel: FAT-fs (sda1): codepage cp437 not found
If the ESP is not mounted to /boot
, the kernel and initramfs files must be copied onto that ESP. They will also need to be replaced regularly every time there is a kernel upgrade. The copy process can be automated by watching the kernel files for change using some systemd units as proposed in EFI System Partition#Using systemd.
esp
will be used throughout this page to denote the ESP mountpoint, i.e. /boot
.
With the ESP mounted to esp
, use bootctl(1) to install systemd-boot into the EFI system partition by running:
# bootctl --path=esp install
This will copy the systemd-boot boot loader to the EFI partition: on a x64 architecture system the two identical binaries esp/EFI/systemd/systemd-bootx64.efi
and esp/EFI/Boot/BOOTX64.EFI
will be transferred to the ESP. It will then set systemd-boot as the default EFI application (default boot entry) loaded by the EFI Boot Manager.
Then, go to the #Configuration section to add boot loaders to make systemd-boot to function properly at boot time.
Updating the EFI boot manager
Whenever there is a new version of systemd-boot, the boot manager must be updated by the user. This can be performed manually or the update can be automatically triggered using pacman hooks. The two approaches are described thereafter.
Manual update
bootctl must be used to update systemd-boot. If the path
parameter is not specified, /efi
, /boot
, and /boot/efi
are checked in turn.
# bootctl update
If the ESP is mounted on a different location, the path
option can be passed as follows:
# bootctl --path=esp update
bootctl --path=esp install
.Automatic update
The package systemd-boot-pacman-hookAUR provides a Pacman hook to automate the update process. Installing the package will add a hook which will be executed every time the systemd package is upgraded.
Alternatively, to replicate what the systemd-boot-pacman-hook package does without installing it, place the following pacman hook in the /etc/pacman.d/hooks/
directory:
/etc/pacman.d/hooks/systemd-boot.hook
[Trigger] Type = Package Operation = Upgrade Target = systemd [Action] Description = Updating systemd-boot When = PostTransaction Exec = /usr/bin/bootctl update
Configuration
Loader configuration
The loader configuration is stored in the file esp/loader/loader.conf
and it is composed of the following options:
default
– default entry to select as defined in #Adding loaders; it is given without the .conf suffix and it can be a wildcard likearch-*
.timeout
– menu timeout in seconds before the default entry is booted. If this is not set, the menu will only be shown onSpace
key (or most other keys actually work too) press during boot.editor
– whether to enable the kernel parameters editor or not.yes
(default) is enabled,no
is disabled; since the user can addinit=/bin/bash
to bypass root password and gain root access, it is strongly recommended to set this option tono
.
Additional options are available starting with systemd v239:
auto-entries
– shows automatic entries for Windows, EFI Shell, and Default Loader if set to1
(default),0
to hide;auto-firmware
– shows entry for rebooting into UEFI firmware settings if set to1
(default),0
to hide;console-mode
– changes UEFI console mode:0
for 80x25,1
for 80x50,2
and above for non-standard modes provided by the device firmware, if any,auto
picks a suitable mode automatically,max
for highest available mode,keep
(default) for the firmware selected mode.
See loader.conf manual for the full list of options.
Example:
esp/loader/loader.conf
default arch timeout 4 editor no
default
andtimeout
can be changed in the boot menu itself and changes will be stored as EFI variables, overriding these options.- A basic loader configuration file is located at
/usr/share/systemd/bootctl/loader.conf
.
Adding loaders
bootctl searches for boot menu items in esp/loader/entries/*.conf
– each file found must contain exactly one loader. 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 parameter orlinux
(see below) is required.options
– command line options to pass to the EFI program or kernel parameters. Optional, but you will need at leastinitrd=efipath
androot=dev
if booting Linux.
For Linux boot, you can also use instead of efi
and options
the following syntax:
linux
andinitrd
followed by the relative path of the corresponding files in the ESP; e.g./vmlinuz-linux
; this will be automatically translated intoefi path
andoptions initrd=path
– this syntax is only supported for convenience and has no differences in function.
An example of a loader file to launch Arch from a partition with the label arch_os and loading the Intel CPU microcode is:
esp/loader/entries/arch.conf
title Arch Linux linux /vmlinuz-linux initrd /intel-ucode.img initrd /initramfs-linux.img options root=LABEL=arch_os rw
bootctl will automatically check at boot time for Windows Boot Manager at the location /EFI/Microsoft/Boot/Bootmgfw.efi
, EFI Shell /shellx64.efi
and EFI Default Loader /EFI/BOOT/bootx64.efi
, as well as specially prepared kernel files found in /EFI/Linux
. When detected, corresponding entries with titles auto-windows
, auto-efi-shell
and auto-efi-default
, respectively, will be generated. These entries do not require manual loader configuration. However, it does not auto-detect other EFI applications (unlike rEFInd), so for booting the Linux kernel, manual configuration entries must be created.
- If you dual-boot Windows, it is strongly recommended to disable its default Fast Start-Up option.
- Remember to load the Intel microcode with
initrd
if applicable, an example is provided in Microcode#systemd-boot. - The root partition can be identified with its
LABEL
or itsPARTUUID
. The latter can be found with the commandblkid -s PARTUUID -o value /dev/sdxY
, wherex
is the device letter andY
is the partition number. This is required only to identify the root partition, not theesp
.
- The available boot entries which have been configured can be listed with the command
bootctl list
. - An example entry file is located at
/usr/share/systemd/bootctl/arch.conf
. - The kernel parameters for scenarios such as LVM, LUKS or dm-crypt can be found on the relevant pages.
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
Preparing kernels for /EFI/Linux
/EFI/Linux is searched for specially prepared kernel files, which bundle the kernel, the init RAM disk (initrd), the kernel command line and /etc/os-release
into one single file. This file can be easily signed for secure boot.
systemd-boot
requires that the os-release
file contain either VERSION_ID
or BUILD_ID
to generate an ID and automatically add the entry, which the Arch os-release
does not. Either maintain your own copy with one of them, or make your bundling script generate it automatically.Put the kernel command line you want to use in a file, and create the bundle file like this:
Kernel packaging command:
objcopy \ --add-section .osrel="/usr/lib/os-release" --change-section-vma .osrel=0x20000 \ --add-section .cmdline="kernel-command-line.txt" --change-section-vma .cmdline=0x30000 \ --add-section .linux="vmlinuz-file" --change-section-vma .linux=0x40000 \ --add-section .initrd="initrd-file" --change-section-vma .initrd=0x3000000 \ "/usr/lib/systemd/boot/efi/linuxx64.efi.stub" "linux.efi"
Optionally sign the linux.efi
file produced above.
Copy linux.efi
into esp/EFI/Linux
.
Support hibernation
Kernel parameters editor with password protection
Alternatively you can install systemd-boot-passwordAUR which supports password
basic configuration option. Use sbpctl generate
to generate a value for this option.
Install systemd-boot-password with the following command:
# sbpctl install esp
With enabled editor you will be prompted for your password before you can edit kernel parameters.
The following keys are used inside the menu:
Up/Down
- select entryEnter
- boot the selected entryd
- 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. It has no effect if theeditor
config option is set to0
.v
- show the gummiboot and UEFI versionQ
- quitP
- print the current configurationh/?
- help
These hotkeys will, when pressed inside the menu or during bootup, directly boot a specific entry:
l
- Linuxw
- Windowsa
- OS Xs
- EFI Shell1-9
- number of entry
Troubleshooting
Installing after booting in BIOS mode
If booted in BIOS mode, you can still install systemd-boot, however this process requires you to tell firmware to launch systemd-boot's EFI file at boot, usually via two ways:
- you have a working EFI Shell somewhere else.
- your firmware interface provides a way of properly setting the EFI file that needs to be loaded at boot time.
If you can do it, 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
( or systemd-bootia32.efi
depending if your system firmware is 32 bit).
Manual entry using efibootmgr
If the 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.
\
) as the separatorMenu does not appear after Windows upgrade
See UEFI#Windows changes boot order.