systemd-boot, sd-boot - A simple UEFI boot manager
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:
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. This information can be displayed using systemd-analyze(1).
The following keys may be used in the boot menu:
↑ (Up), ↓ (Down), j, k, PageUp, PageDown, Home, End
Ctrl + l
The following keys may be used during bootup or in the boot menu to directly boot a specific entry:
1, 2, 3, 4, 5, 6, 7, 8, 9
In the editor, most keys simply insert themselves, but the following keys may be used to perform additional actions:
← (Left), → (Right), Home, End
Ctrl + k
Ctrl + w, Alt + Backspace
Alt + d
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 +/-.
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 are read from /loader/entries/ on the ESP. Unified kernel boot entries following the Boot Loader Specification are read from /EFI/Linux/ on the ESP.
- Boot Loader Specification
- Boot Loader Interface