systemd systemd-boot 7 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: Boot entries defined with Boot Loader Specification 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, 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-install8 may be used to copy kernel images onto the ESP and to generate description files compliant with the Boot Loader Specification. bootctl1 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-analyze1. 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 +/-. 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.conf5. 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. bootctl1, loader.conf5, Boot Loader Specification, Boot Loader Interface