systemd/man/loader.conf.xml

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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
  "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<refentry id="loader.conf" conditional='HAVE_GNU_EFI'
    xmlns:xi="http://www.w3.org/2001/XInclude">
  <refentryinfo>
    <title>loader.conf</title>
    <productname>systemd</productname>
  </refentryinfo>

  <refmeta>
    <refentrytitle>loader.conf</refentrytitle>
    <manvolnum>5</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>loader.conf</refname>
    <refpurpose>Configuration file for systemd-boot</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <para><filename><replaceable>ESP</replaceable>/loader/loader.conf</filename>,
    <filename><replaceable>ESP</replaceable>/loader/entries/*.conf</filename>
    </para>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para>
    <citerefentry><refentrytitle>systemd-boot</refentrytitle><manvolnum>7</manvolnum></citerefentry>
    will read <filename><replaceable>ESP</replaceable>/loader/loader.conf</filename> and any files with the
    <literal>.conf</literal> extension under
    <filename><replaceable>ESP</replaceable>/loader/entries/</filename> on the EFI system partition (ESP).
    </para>

    <para>Each configuration file must consist of an option name, followed by
    whitespace, and the option value. <literal>#</literal> may be used to start
    a comment line. Empty and comment lines are ignored.</para>

    <para>Boolean arguments may be written as
    <literal>yes</literal>/<literal>y</literal>/<literal>true</literal>/<literal>t</literal>/<literal>on</literal>/<literal>1</literal> or
    <literal>no</literal>/<literal>n</literal>/<literal>false</literal>/<literal>f</literal>/<literal>off</literal>/<literal>0</literal>.
    </para>
  </refsect1>

  <refsect1>
    <title>Options</title>

    <para>The following configuration options in <filename>loader.conf</filename> are understood:</para>

    <variablelist>
      <varlistentry>
        <term>default</term>

        <listitem><para>A glob pattern to select the default entry. The default entry
        may be changed in the boot menu itself, in which case the name of the
        selected entry will be stored as an EFI variable, overriding this option.
        </para>

        <para>If set to <literal>@saved</literal> the chosen entry will be saved as an EFI variable
        on every boot and automatically selected the next time the boot loader starts.</para>

        <table>
          <title>Automatically detected entries will use the following names:</title>

          <tgroup cols='2'>
            <colspec colname='name' />
            <colspec colname='expl' />
            <thead>
              <row>
                <entry>Name</entry>
                <entry>Description</entry>
              </row>
            </thead>
            <tbody>
              <row>
                <entry>auto-efi-default</entry>
                <entry>EFI Default Loader</entry>
              </row>
              <row>
                <entry>auto-efi-shell</entry>
                <entry>EFI Shell</entry>
              </row>
              <row>
                <entry>auto-osx</entry>
                <entry>macOS</entry>
              </row>
              <row>
                <entry>auto-reboot-to-firmware-setup</entry>
                <entry>Reboot Into Firmware Interface</entry>
              </row>
              <row>
                <entry>auto-windows</entry>
                <entry>Windows Boot Manager</entry>
              </row>
            </tbody>
          </tgroup>
        </table></listitem>
      </varlistentry>

      <varlistentry>
        <term>timeout</term>

        <listitem><para>How long the boot menu should be shown before the default
        entry is booted, in seconds. This may be changed in the boot menu itself and
        will be stored as an EFI variable in that case, overriding this option.
        </para>

        <para>If set to <literal>menu-hidden</literal> or <literal>0</literal> no menu
        is shown and the default entry will be booted immediately. The menu can be shown
        by pressing and holding a key before systemd-boot is launched. Setting this to
        <literal>menu-force</literal> disables the timeout while always showing the menu.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>console-mode</term>

        <listitem><para>This option configures the resolution of the console. Takes a
        number or one of the special values listed below. The following values may be
        used:</para>

        <variablelist>
          <varlistentry>
            <term>0</term>
            <listitem>
              <para>Standard UEFI 80x25 mode</para>
            </listitem>
          </varlistentry>

          <varlistentry>
            <term>1</term>
            <listitem>
              <para>80x50 mode, not supported by all devices</para>
            </listitem>
          </varlistentry>

          <varlistentry>
            <term>2</term>
            <listitem>
              <para>the first non-standard mode provided by the device
              firmware, if any</para>
            </listitem>
          </varlistentry>

          <varlistentry>
            <term>auto</term>
            <listitem>
              <para>Pick a suitable mode automatically using heuristics</para>
            </listitem>
          </varlistentry>

          <varlistentry>
            <term>max</term>
            <listitem>
              <para>Pick the highest-numbered available mode</para>
            </listitem>
          </varlistentry>

          <varlistentry>
            <term>keep</term>
            <listitem>
              <para>Keep the mode selected by firmware (the default)</para>
            </listitem>
          </varlistentry>
        </variablelist>

        </listitem>
      </varlistentry>

      <varlistentry>
        <term>editor</term>

        <listitem><para>Takes a boolean argument. Enable (the default) or disable the
        editor. The editor should be disabled if the machine can be accessed by
        unauthorized persons.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term>auto-entries</term>

        <listitem><para>Takes a boolean argument. Enable (the default) or disable
        entries for other boot entries found on the boot partition. In particular,
        this may be useful when loader entries are created to show replacement
        descriptions for those entries.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term>auto-firmware</term>

        <listitem><para>A boolean controlling the presence of the "Reboot into firmware" entry
        (enabled by default). If this is disabled, the firmware interface may still be reached
        by using the <keycap>f</keycap> key.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term>beep</term>

        <listitem><para>Beep n times when the n-th entry in the boot menu is shown (default disabled).
        Currently, only x86 is supported, where it uses the PC speaker.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term>reboot-for-bitlocker</term>

        <listitem><para>Work around BitLocker requiring a recovery key when the boot loader was
        updated (enabled by default).</para>

        <para>Try to detect BitLocker encrypted drives along with an active TPM. If both are found
        and Windows Boot Manager is selected in the boot menu, set the <literal>BootNext</literal>
        EFI variable and restart the system. The firmware will then start Windows Boot Manager
        directly, leaving the TPM PCRs in expected states so that Windows can unseal the encryption
        key. This allows systemd-boot to be updated without having to provide the recovery key for
        BitLocker drive unlocking.</para>

        <para>Note that the PCRs that Windows uses can be configured with the
        <literal>Configure TPM platform validation profile for native UEFI firmware configurations</literal>
        group policy under <literal>Computer Configuration\Administrative Templates\Windows Components\BitLocker Drive Encryption</literal>.
        When secure boot is enabled, changing this to PCRs <literal>0,2,7,11</literal> should be safe.
        The TPM key protector needs to be removed and then added back for the PCRs on an already
        encrypted drive to change. If PCR 4 is not measured, this setting can be disabled to speed
        up booting into Windows.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term>random-seed-mode</term>

        <listitem><para>Takes one of <literal>off</literal>, <literal>with-system-token</literal> and
        <literal>always</literal>. If <literal>off</literal> no random seed data is read off the ESP, nor
        passed to the OS. If <literal>with-system-token</literal> (the default)
        <command>systemd-boot</command> will read a random seed from the ESP (from the file
        <filename>/loader/random-seed</filename>) only if the <varname>LoaderSystemToken</varname> EFI
        variable is set, and then derive the random seed to pass to the OS from the combination. If
        <literal>always</literal> the boot loader will do so even if <varname>LoaderSystemToken</varname> is
        not set. This mode is useful in environments where protection against OS image reuse is not a
        concern, and the random seed shall be used even with no further setup in place. Use <command>bootctl
        random-seed</command> to initialize both the random seed file in the ESP and the system token EFI
        variable.</para>

        <para>See <ulink url="https://systemd.io/RANDOM_SEEDS">Random Seeds</ulink> for further
        information.</para></listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Example</title>

    <programlisting># /boot/efi/loader/loader.conf
timeout 0
default 01234567890abcdef1234567890abdf0-*
editor no
    </programlisting>

    <para>The menu will not be shown by default (the menu can still be shown by
    pressing and holding a key during boot). One of the entries with files with a
    name starting with <literal>01234567890abcdef1234567890abdf0-</literal> will be
    selected by default. If more than one entry matches, the one with the highest
    priority will be selected (generally the one with the highest version number).
    The editor will be disabled, so it is not possible to alter the kernel command
    line.</para>
  </refsect1>

  <refsect1>
      <title>See Also</title>
      <para>
        <citerefentry><refentrytitle>systemd-boot</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
        <citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
      </para>
  </refsect1>
</refentry>