<?xml version='1.0'?> <!--*-nxml-*-->
-<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
-
<!-- SPDX-License-Identifier: LGPL-2.1+ -->
<refentry id="systemd-boot" conditional='ENABLE_EFI'
<refsect1>
<title>Description</title>
- <para><command>systemd-boot</command> (short: <command>sd-boot</command>) 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.</para>
+ <para><command>systemd-boot</command> (short: <command>sd-boot</command>) 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. <command>systemd-boot</command> supports systems with UEFI firmware only.</para>
<para>systemd-boot loads boot entry information from the EFI system partition (ESP), usually mounted at
- <filename>/boot</filename>, <filename>/efi</filename>, or <filename>/boot/efi</filename> 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 <option>CONFIG_EFI_STUB</option> 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:</para>
+ <filename>/efi/</filename>, <filename>/boot/</filename>, or <filename>/boot/efi/</filename> during OS
+ runtime, as well as from the Extended Boot Loader partition if it exists (usually mounted to
+ <filename>/boot/</filename>). Configuration file fragments, kernels, initrds and other EFI images to boot
+ generally need to reside on the ESP or the Extended Boot Loader partition. Linux kernels must be built
+ with <option>CONFIG_EFI_STUB</option> 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:</para>
<itemizedlist>
<listitem><para>Boot entries defined with <ulink
- url="https://systemd.io/BOOT_LOADER_SPECIFICATION">Boot Loader
- Specification</ulink> description files located in <filename>/loader/entries/</filename> on the ESP. These
- usually describe Linux kernel images with associated initrd images, but alternatively may also describe
- arbitrary other EFI executables.</para></listitem>
+ url="https://systemd.io/BOOT_LOADER_SPECIFICATION">Boot Loader Specification</ulink> description files
+ located in <filename>/loader/entries/</filename> on the ESP and the Extended Boot Loader
+ Partition. These usually describe Linux kernel images with associated initrd images, but alternatively
+ may also describe arbitrary other EFI executables.</para></listitem>
<listitem><para>Unified kernel images following the <ulink
- url="https://systemd.io/BOOT_LOADER_SPECIFICATION">Boot Loader
- Specification</ulink>, as executable EFI binaries in <filename>/EFI/Linux/</filename> on the ESP.
+ url="https://systemd.io/BOOT_LOADER_SPECIFICATION">Boot Loader Specification</ulink>, as executable EFI
+ binaries in <filename>/EFI/Linux/</filename> on the ESP and the Extended Boot Loader Partition.
</para></listitem>
<listitem><para>The Microsoft Windows EFI boot manager, if installed</para></listitem>
<listitem><para>A reboot into the UEFI firmware setup option, if supported by the firmware</para></listitem>
</itemizedlist>
- <para><citerefentry><refentrytitle>kernel-install</refentrytitle><manvolnum>8</manvolnum></citerefentry> may be
- used to copy kernel images onto the ESP and to generate description files compliant with the Boot Loader
- Specification. <citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> may be
- used from a running system to locate the ESP, list available entries, and install systemd-boot itself.</para>
+ <para><citerefentry><refentrytitle>kernel-install</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+ may be used to copy kernel images onto the ESP or the Extended Boot Loader Partition and to generate
+ description files compliant with the Boot Loader
+ Specification. <citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+ may be used from a running system to locate the ESP and the Extended Boot Loader Partition, list
+ available entries, and install <command>systemd-boot</command> itself.</para>
<para>systemd-boot will provide information about the time spent in UEFI firmware using the <ulink
url="https://systemd.io/BOOT_LOADER_INTERFACE">Boot Loader Interface</ulink>. This information can be displayed
<refsect1>
<title>Files</title>
- <para>The files systemd-boot reads generally reside on the UEFI ESP which is usually mounted to
- <filename>/boot/</filename>, <filename>/efi/</filename> or <filename>/boot/efi</filename> during OS
- runtime. systemd-boot reads runtime configuration such as the boot timeout and default entry from
- <filename>/loader/loader.conf</filename> on the ESP (in combination with data read from EFI variables). See
- <citerefentry><refentrytitle>loader.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>. Boot entry
- description files following the <ulink
- url="https://systemd.io/BOOT_LOADER_SPECIFICATION">Boot Loader
- Specification</ulink> are read from <filename>/loader/entries/</filename> on the ESP. Unified kernel boot entries
- following the <ulink url="https://systemd.io/BOOT_LOADER_SPECIFICATION">Boot
- Loader Specification</ulink> are read from <filename>/EFI/Linux/</filename> on the ESP.</para>
+ <para>The files <command>systemd-boot</command> processes generally reside on the UEFI ESP which is
+ usually mounted to <filename>/efi/</filename>, <filename>/boot/</filename> or
+ <filename>/boot/efi/</filename> during OS runtime. It also processes files on the Extended Boot Loader
+ partition which is typically mounted to <filename>/boot/</filename>, if it
+ exists. <command>systemd-boot</command> reads runtime configuration such as the boot timeout and default
+ entry from <filename>/loader/loader.conf</filename> on the ESP (in combination with data read from EFI
+ variables). See
+ <citerefentry><refentrytitle>loader.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>. Boot
+ entry description files following the <ulink url="https://systemd.io/BOOT_LOADER_SPECIFICATION">Boot
+ Loader Specification</ulink> are read from <filename>/loader/entries/</filename> on the ESP and the
+ Extended Boot Loader partition. Unified kernel boot entries following the <ulink
+ url="https://systemd.io/BOOT_LOADER_SPECIFICATION">Boot Loader Specification</ulink> are read from
+ <filename>/EFI/Linux/</filename> on the ESP and the Extended Boot Loader partition.</para>
</refsect1>
<refsect1>
UUID <literal>4a67b082-0a4c-41cf-b6c7-440b29bb8c4</literal>, for communication between the OS and the boot
loader:</para>
- <variablelist>
+ <variablelist class='efi-variables'>
<varlistentry>
<term><varname>LoaderBootCountPath</varname></term>
<listitem><para>If boot counting is enabled, contains the path to the file in whose name the boot counters are
<para><command>systemd-boot</command> implements a simple boot counting mechanism on top of the <ulink
url="https://systemd.io/BOOT_LOADER_SPECIFICATION">Boot Loader Specification</ulink>, for automatic and unattended
- fallback to older kernel versions/boot loader entries when a specific entry continously fails. Any boot loader
+ fallback to older kernel versions/boot loader entries when a specific entry continuously fails. Any boot loader
entry file and unified kernel image file that contains a <literal>+</literal> followed by one or two numbers (if
two they need to be separated by a <literal>-</literal>), before the <filename>.conf</filename> or
<filename>.efi</filename> suffix is subject to boot counting: the first of the two numbers ('tries left') is
projects / thirdparty / systemd.git / blobdiff