SYSTEMD-BOOT(7)

NAME
systemd-boot, sd-boot - A simple UEFI boot manager

DESCRIPTION

systemd-boot (short: sd-boot) is a simple UEFI boot manager. It provides a graphical menu to select the entry to boot and an editor for the kernel command line. systemd-boot supports systems with UEFI firmware only.

systemd-boot loads boot entry information from the EFI system partition (ESP), usually mounted at /boot, /efi, or /boot/efi during OS runtime. Configuration file fragments, kernels, initrds and other EFI images to boot generally need to reside on the ESP. Linux kernels must be built with CONFIG_EFI_STUB to be able to be directly executed as an EFI image. During boot systemd-boot automatically assembles a list of boot entries from the following sources:

    • Boot entries defined with Boot Loader Specification[1] description files located in /loader/entries/ on the ESP. These usually describe Linux kernel images with associated initrd images, but alternatively may also describe arbitrary other EFI executables.

    • Unified kernel images following the Boot Loader Specification[1], as executable EFI binaries in /EFI/Linux/ on the ESP.

    • The Microsoft Windows EFI boot manager, if installed

    • The Apple MacOS X boot manager, if installed

    • The EFI Shell binary, if installed

    • A reboot into the UEFI firmware setup option, if supported by the firmware

kernel-install(8) may be used to copy kernel images onto the ESP and to generate description files compliant with the Boot Loader Specification. bootctl(1) may be used from a running system to locate the ESP, list available entries, and install systemd-boot itself.

systemd-boot will provide information about the time spent in UEFI firmware using the Boot Loader Interface[2]. This information can be displayed using systemd-analyze(1).

KEY BINDINGS

The following keys may be used in the boot menu:

↑ (Up), ↓ (Down), j, k, PageUp, PageDown, Home, End
    Navigate up/down in the entry list

↵ (Enter)
    Boot selected entry

d
    Make selected entry the default

e
    Edit the kernel command line for selected entry

+, t
    Increase the timeout before default entry is booted

-, T
    Decrease the timeout

v
    Show systemd-boot, UEFI, and firmware versions

P
    Print status

Q
    Quit

h, ?
    Show a help screen

Ctrl + l
    Reprint the screen

The following keys may be used during bootup or in the boot menu to directly boot a specific entry:

l
    Linux

w
    Windows

a
    OS X

s
    EFI shell

1, 2, 3, 4, 5, 6, 7, 8, 9
    Boot entry number 1 ... 9

In the editor, most keys simply insert themselves, but the following keys may be used to perform additional actions:

← (Left), → (Right), Home, End
    Navigate left/right

Esc
    Abort the edit and quit the editor

Ctrl + k
    Clear the command line

Ctrl + w, Alt + Backspace
    Delete word backwards

Alt + d
    Delete word forwards

↵ (Enter)
    Boot entry with the edited command line

Note that unless configured otherwise in the UEFI firmware, systemd-boot will use the US keyboard layout, so key labels might not match for keys like +/-.

FILES

The files systemd-boot reads generally reside on the UEFI ESP which is usually mounted to /boot/, /efi/ or /boot/efi during OS runtime. systemd-boot reads runtime configuration such as the boot timeout and default entry from /loader/loader.conf on the ESP (in combination with data read from EFI variables). See loader.conf(5). Boot entry description files following the Boot Loader Specification[1] are read from /loader/entries/ on the ESP. Unified kernel boot entries following the Boot Loader Specification[1] are read from /EFI/Linux/ on the ESP.

SEE ALSO

bootctl(1), loader.conf(5), Boot Loader Specification[1], Boot Loader Interface[2]

NOTES

1.  Boot Loader Specification
    https://github.com/systemd/systemd/blob/master/doc/BOOT_LOADER_SPECIFICATION.md

2.  Boot Loader Interface
    https://www.freedesktop.org/wiki/Software/systemd/BootLoaderInterface