NAME¶

DESCRIPTION¶

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[2]. This information can be displayed using systemd-analyze(1).

KEY BINDINGS¶

↑ (Up), ↓ (Down), j, k, PageUp, PageDown, Home, End

↵ (Enter)

d

e

+, t

-, T

v

P

Q

h, ?

Ctrl+l

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

l

w

a

s

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

Esc

Ctrl+k

Ctrl+w, Alt+Backspace

Alt+d

↵ (Enter)

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¶

EFI VARIABLES¶

LoaderBootCountPath

LoaderConfigTimeout, LoaderConfigTimeoutOneShot

LoaderDevicePartUUID

LoaderEntries

LoaderEntryDefault, LoaderEntryOneShot

LoaderEntrySelected

LoaderFeatures

LoaderFirmwareInfo, LoaderFirmwareType

LoaderImageIdentifier

LoaderInfo

LoaderTimeExecUSec, LoaderTimeInitUSec, LoaderTimeMenuUsec

BOOT COUNTING¶

Generally, when new entries are added to the boot loader, they first start out in 'indeterminate' state, i.e. with a 'tries left' counter greater than zero. The boot entry remains in this state until either it managed to complete a full boot successfully at least once (in which case it will be in 'good' state) — or the 'tries left' counter reaches zero (in which case it will be in 'bad' state).

Example: let's say a boot loader entry file foo.conf is set up for 3 boot tries. The installer will hence create it under the name foo+3.conf. On first boot, the boot loader will rename it to foo+2-1.conf. If that boot does not complete successfully, the boot loader will rename it to foo+1-2.conf on the following boot. If that fails too, it will finally be renamed foo+0-3.conf by the boot loader on next boot, after which it will be considered 'bad'. If the boot succeeds however the entry file will be renamed to foo.conf by the OS, so that it is considered 'good' from then on.

The boot menu takes the 'tries left' counter into account when sorting the menu entries: entries in 'bad' state are ordered at the end of the list, and entries in 'good' or 'indeterminate' at the beginning. The user can freely choose to boot any entry of the menu, including those already marked 'bad'. If the menu entry to boot is automatically determined, this means that 'good' or 'indeterminate' entries are generally preferred (as the top item of the menu is the one booted by default), and 'bad' entries will only be considered if there are no 'good' or 'indeterminate' entries left.

The kernel-install(8) kernel install framework optionally sets the initial 'tries left' counter to the value specified in /etc/kernel/tries when a boot loader entry is first created.

SEE ALSO¶

NOTES¶

1.

Boot Loader Specification

2.

Boot Loader Interface