systemd-boot

Related articles

• Arch boot process
• Boot loaders
• Secure Boot
• Unified Extensible Firmware Interface

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.

Warning: If ESP is not mounted to /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

Note: This is also the command to use when migrating from gummiboot, before removing that package. If that package has already been removed, however, run bootctl --path=esp install.

Automatic update

The package systemd-boot-pacman-hook^AUR 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 like arch-*.
• timeout – menu timeout in seconds before the default entry is booted. If this is not set, the menu will only be shown on Space 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 add init=/bin/bash to bypass root password and gain root access, it is strongly recommended to set this option to no.

Additional options are available starting with systemd v239:

• auto-entries – shows automatic entries for Windows, EFI Shell, and Default Loader if set to 1 (default), 0 to hide;
• auto-firmware – shows entry for rebooting into UEFI firmware settings if set to 1 (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

Tip:

• default and timeout 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 or linux (see below) is required.
• options – command line options to pass to the EFI program or kernel parameters. Optional, but you will need at least initrd=efipath and root=dev if booting Linux.

For Linux boot, you can also use instead of efi and options the following syntax:

• linux and initrd followed by the relative path of the corresponding files in the ESP; e.g. /vmlinuz-linux; this will be automatically translated into efi path and options 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.

Note:

• 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 its PARTUUID. The latter can be found with the command blkid -s PARTUUID -o value /dev/sdxY, where x is the device letter and Y is the partition number. This is required only to identify the root partition, not the esp.

Tip:

• 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.

Note: 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

See Suspend and hibernate.

Kernel parameters editor with password protection

Alternatively you can install systemd-boot-password^AUR 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.

Keys inside the boot menu

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. It has no effect if the editor config option is set to 0.
• 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

Installing after booting in BIOS mode

Warning: This is not recommended.

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).

Note: The firmware interface of Dell Latitude series provides everything you need to setup EFI boot but the EFI Shell won't be able to write to the computer's ROM.

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.

Note: The path to the EFI image must use the backslash (\) as the separator

Menu does not appear after Windows upgrade

See UEFI#Windows changes boot order.

See also

• http://www.freedesktop.org/wiki/Software/systemd/systemd-boot/
• https://github.com/systemd/systemd/tree/master/src/boot/efi