# 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 the systemd, which is installed on an Arch system by default.

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.

Warning: systemd-boot simply provides a boot menu for EFISTUB kernels. In case you have issues booting EFISTUB kernels like in FS#33745, you should use a boot loader which does not use EFISTUB, like GRUB, Syslinux or any other Boot loader which does not solely rely on UEFI.

## Installation

### EFI boot

1. Make sure you are booted in UEFI mode.
2. Verify your EFI variables are accessible.
3. Mount your EFI System Partition(ESP) properly. `esp` is used to denote the mountpoint in this article.
   Note: systemd-boot cannot load EFI binaries from other partitions. It is therefore recommended to mount your ESP to `/boot`. See #Updating for more information and work-around, in case you want to separate `/boot` from the ESP.
4. If the ESP will not be used as the /boot partition then copy your kernel and initramfs onto that ESP.
   Note: For a way to automatically keep the kernel updated on the ESP, have a look at the EFISTUB article for some systemd units that can be adapted. If your efi partition is using automount, you may need to add `vfat` to a file in `/etc/modules-load.d/` to ensure the current running kernel has the `vfat` module loaded at boot, before any kernel update happens that could replace the module for the currently running version making the mounting of `/boot/efi` impossible until reboot.
5. 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.
6. Finally you must configure the boot loader to function properly.

### Legacy boot

Warning: This is not the recommended process.

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.

Note: E.g. on Dell's Latitude series, the firmware interface provides everything you need to setup EFI boot, and the EFI Shell won't be able to write to the computer's ROM.

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 (`man bootctl`, `man systemd-efi-boot-generator`) 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=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`.

## 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 like `arch-*`

- `timeout` – menu timeout in seconds. If this is not set, the menu will only be shown on key press during boot.

- `editor` - whether to enable the kernel parameters editor or not. `1` (default) is to enable, `0` is to disable. Since the user can add `init=/bin/bash` to bypass root password and gain root access, it's strongly recommended to set this option to `0`.

Example:

    esp/loader/loader.conf

    default  arch
    timeout  4
    editor   0

Note: The first 2 options can be changed in the boot menu itself, which will store them as EFI variables.
Tip: A basic configuration file example is located at `/usr/share/systemd/bootctl`.

### Adding boot entries

Note:

- bootctl will automatically check for "Windows Boot Manager" (`\EFI\Microsoft\Boot\Bootmgfw.efi`), "EFI Shell" (`\shellx64.efi`) and "EFI Default Loader" (`\EFI\Boot\bootx64.efi`) at boot time. Where detected, entries will also automatically be generated for them as well. These entries don't require loader configuration entries. However, it does not auto-detect other EFI applications (unlike rEFInd), so for booting the 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.
- You can find the `PARTUUID` for your root partition 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 for your root partition, not `esp`.

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 or `linux` (see below) is required.

- `options` – command line options to pass to the EFI program or kernel boot parameters. Optional, but you will need at least `initrd=efipath` and `root=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 `LABEL`s).

Tip: An example entry file is located at `/usr/share/systemd/bootctl`.

#### LVM root installations

Warning: systemd-boot cannot be used without a separate `/boot` filesystem outside of LVM.

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) using the `encrypt` mkinitcpio hook:

    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. `mapped-name` is whatever you want it to be called. See Dm-crypt/System configuration#Boot loader.

If you are using LVM, your cryptdevice line will look like this:

    esp/loader/entries/arch-encrypted-lvm.conf

    title Arch Linux Encrypted LVM
    linux /vmlinuz-linux
    initrd /initramfs-linux.img
    options cryptdevice=UUID=<UUID>:MyVolGroup root=/dev/mapper/MyVolGroup-MyVolRoot quiet rw

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.`

#### ZFS root installations

When booting from a ZFS dataset, add `zfs=<root dataset>` to the `options` line. Here the root dataset has been set to 'zroot/ROOT/default':

    esp/loader/entries/arch-zfs.conf

    title          Arch Linux ZFS
    linux          /vmlinuz-linux
    initrd         /initramfs-linux.img
    options        zfs=zroot/ROOT/default rw

When booting off of a ZFS dataset ensure that it has had the `bootfs` property set with `zpool set bootfs=<root dataset> <zpool>`.

#### 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

This article or section needs expansion.

Reason: Add example on how to boot into EFI firmware setup. (Discuss in Talk:Systemd-boot#)

### Support hibernation

See Suspend and hibernate.

## 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

### 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

See UEFI#Windows changes boot order.

## See also

- http://www.freedesktop.org/wiki/Software/systemd/systemd-boot/

Category:

- Boot loaders

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