systemd I wrote this page Zbigniew Jędrzejewski-Szmek zbyszek@in.waw.pl sd-boot 7 sd-boot A simple UEFI boot manager systemd-boot or sd-boot is a simple UEFI boot manager, previously known as gummiboot. It provides a graphical menu to select the entry to boot and an editor for the kernel command line. sd-boot is only useful on machines using UEFI. sd-boot loads information from the EFI system partition (ESP), usually mounted at /boot, /efi, or /boot/efi. Configuration file fragments, kernels, initrds, other EFI images 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. sd-boot will automatically list other boot entries registered as EFI boot variables, and a list of kernels from configuration files following the Boot Loader Specification located under /loader/entries/ on the ESP. kernel-install8 may be used to copy kernel images onto the ESP and to generate entries compliant with the Boot Loader Specification. bootctl1 may be used from a running system to locate the ESP, list available entries, and install sd-boot itself. sd-boot will provide information about the time spent in UEFI firmware using the Boot Loader Interface. This information can be displayed using systemd-analyze1. sd-boot reads configuration like the timeout and default entry from /loader/loader.conf on the ESP and from EFI variables. See loader.conf5. 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 sd-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 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, sd-boot will use the US keyboard layout, so key labels might not match for keys like +/-. bootctl1, loader.conf5, Boot Loader Specification, Boot Loader Interface, upstream wiki page