Difference between revisions of "Systemd-boot"
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== Inside the boot menu ==
== Inside the boot menu ==
Revision as of 11:25, 12 March 2013
Gummiboot is a UEFI boot manager written by Kay Sievers and Harald Hoyer. It is simple to configure, but can only start EFI executables, the Linux kernel (with CONFIG_EFI_STUB enabled), grub.efi, and such.
/boot. If your ESP is mounted on
/boot/efiyou have to call the following gummiboot install command with the additional
--pathswitch. This also means that gummiboot will not be able to update itself automatically and you will have to call
gummiboot --path /boot/efi updateafter every package update. It is therefore strongly recommended to mount your ESP to
/bootif you use gummiboot.
Installfrom [extra] and run the following to install gummiboot:
# gummiboot install
This will automatically copy the gummiboot binary to your EFI System Partition and create a boot entry in the EFI Boot Manager. However, creating the boot entry requires that you are already running in EFI mode and are running kernel 3.8 which is currently still in [testing]. If you are still running kernel 3.7 or have not booted in EFI mode, creating the boot entry will fail. You should however still be able to boot gummiboot as it copies the binary to the default EFI binary location on your ESP (
/boot/EFI/BOOT/BOOTX64.EFI on x64 systems). Note that the installing process only has to be done once, updating will happen automatically as long as your ESP is mounted on
The basic configuration is kept in
$esp/loader/loader.conf, with just two possible configuration options:
default– default entry to select (without the
.confsuffix); can be a wildcard like
timeout– menu timeout in seconds. If this is not set, the menu will only be shown when you hold the space key while booting.
default arch timeout 4
Note that both options can be changed in the boot menu itself, which will store them as EFI variables.
Adding boot entries
If you have separate partitions for
/boot/efi, you must copy the kernel and initramfs to the EFI partition. Gummiboot does not support loading kernels from other partitions than itself. See UEFI_Bootloaders#Sync_EFISTUB_Kernel on how to automate this copy.
Gummiboot searches for boot menu items in
$esp/loader/entries/*.conf – each file found must contain exactly one boot entry. The possible options are:
title– operating system name. Required.
version– kernel version, shown only when multiple entries with same title exist. Optional.
machine-id– machine identifier from
/etc/machine-id, shown only when multiple entries with same title+version exist. Optional.
efi– EFI program to start; e.g.
/vmlinuz-linux. Either this or
linux(see below) is required.
options– Command-line options to pass to the EFI program. Optional, but you will need at least
root=devif booting Linux.
For Linux, you can specify
linux path-to-vmlinuz and
initrd path-to-initramfs; this will be automatically translated to
efi path and
options initrd=path – this syntax is only supported for convenience and has no differences in function.
An example entry for Arch Linux:
title Arch Linux linux /vmlinuz-linux initrd /initramfs-linux.img options root=PARTUUID=14420948-2cea-4de7-b042-40f67c618660 ro
You can also add other EFI programs such as
\EFI\Microsoft\Boot\Bootmgfw.efi (the Windows 7 boot manager). The EFI Shell, if installed, will be shown automatically.
title UEFI Shell efi \shellx64.efi
TODO: document keybindings from http://freedesktop.org/wiki/Software/gummiboot
Transferring to new HDD causes breakage
Twice now I have transferred my installation from one disk to another, ESP included, and both times this broke my gummiboot setup. With a lot of trial and error, I have discovered that gummiboot does not like configuration files that have been tranfserred from one disk to another (I used rsync).
To solve this, delete the $ESP/loader directory and all of its contents, and recreate the necessary configuration files.
Though it has no additional info, here is my relevent forum thread.