1 | <?xml version="1.0" encoding="ISO-8859-1"?>
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2 | <!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
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3 | "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
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4 | <!ENTITY % general-entities SYSTEM "../../../general.ent">
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5 | %general-entities;
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6 | ]>
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7 |
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8 | <sect1 id="grub-setup" xreflabel="Using GRUB to Set Up the Boot Process with UEFI">
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9 | <?dbhtml filename="grub-setup.html"?>
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10 |
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11 |
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12 | <title>Using GRUB to Set Up the Boot Process with UEFI</title>
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13 |
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14 | <sect2>
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15 | <title>Turn Off Secure Boot</title>
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16 |
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17 | <para>
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18 | BLFS does not have the essential packages to support Secure Boot. To
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19 | set up the boot process with GRUB and UEFI in BLFS, Secure
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20 | Boot must be turned off from the configuration interface of the
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21 | firmware. Read the documentation provided by the manufacturer of your
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22 | system to find out how.
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23 | </para>
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24 | </sect2>
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25 |
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26 | <sect2 role="kernel" id="uefi-kernel">
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27 | <title>Kernel Configuration for UEFI support</title>
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28 |
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29 | <para>
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30 | Enable the following options in the kernel configuration and recompile
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31 | the kernel if necessary:
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32 | </para>
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33 |
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34 | <xi:include xmlns:xi="http://www.w3.org/2001/XInclude"
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35 | href="grub-setup-kernel.xml"/>
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36 |
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37 | <variablelist>
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38 | <title>The meaning of the configuration options:</title>
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39 |
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40 | <varlistentry>
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41 | <term><parameter>CONFIG_PARTITION_ADVANCED</parameter></term>
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42 | <listitem>
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43 | <para>If it's not enabled,
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44 | <parameter>CONFIG_EFI_PARTITION</parameter> will be enabled
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45 | automatically. But when it's enabled, you must set
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46 | <parameter>CONFIG_EFI_PARTITION</parameter> to enabled as
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47 | well.</para>
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48 | </listitem>
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49 | </varlistentry>
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50 |
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51 | <varlistentry>
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52 | <term>
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53 | <parameter>CONFIG_SYSFB_SIMPLEFB</parameter>,
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54 | <parameter>CONFIG_DRM</parameter>,
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55 | <parameter>CONFIG_DRM_FBDEV_EMULATION</parameter>,
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56 | <parameter>CONFIG_DRM_SIMPLEDRM</parameter>,
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57 | <parameter>CONFIG_FB</parameter>, and
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58 | <parameter>CONFIG_FRAMEBUFFER_CONSOLE</parameter></term>
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59 | <listitem>
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60 | <para>The combination of these options provides the Linux console
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61 | support on top of the UEFI framebuffer. To allow the kernel to
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62 | print debug messages at an early boot stage, they shouldn't be
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63 | built as kernel modules unless an initramfs will be used.</para>
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64 | </listitem>
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65 | </varlistentry>
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66 |
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67 | </variablelist>
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68 |
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69 | <indexterm zone="grub-setup uefi-kernel">
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70 | <primary sortas="d-uefi">UEFI</primary>
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71 | </indexterm>
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72 | </sect2>
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73 |
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74 | <sect2>
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75 | <title>Create an Emergency Boot Disk</title>
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76 |
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77 | <para>
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78 | Ensure that an emergency boot disk is ready to <quote>rescue</quote>
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79 | the system in case the system becomes un-bootable. To make an
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80 | emergency boot disk with GRUB for an EFI based system, find a spare
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81 | USB flash drive and create a
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82 | <systemitem class="filesystem">vfat</systemitem> file system on it.
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83 | Install <xref linkend="dosfstools"/> first, then
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84 | as the <systemitem class="username">root</systemitem> user:
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85 | </para>
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86 |
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87 | <warning>
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88 | <para>
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89 | The following command will erase all directories and files in the
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90 | partition. Make sure your USB flash drive contains no data which
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91 | will be needed, and change <userinput>sdx1</userinput> to the
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92 | device node corresponding to the first partition of the USB flash
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93 | drive. Be careful not to overwrite your hard drive with a typo!
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94 | </para>
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95 | </warning>
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96 |
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97 | <screen role="nodump"><userinput>mkfs.vfat /dev/sdx1</userinput></screen>
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98 |
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99 | <para>
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100 | Still as the <systemitem class="username">root</systemitem> user, use
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101 | the <command>fdisk</command> utility to set the first partition
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102 | of the USB flash drive to be an <quote>EFI system</quote> partition
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103 | (change <userinput>sdx</userinput> to the device node corresponding
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104 | to your USB flash drive):
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105 | </para>
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106 |
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107 | <screen role="nodump"><userinput>fdisk /dev/sdx</userinput>
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108 | <literal>
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109 | Welcome to fdisk (util-linux 2.38.1).
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110 | Changes will remain in memory only, until you decide to write them.
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111 | Be careful before using the write command.
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112 |
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113 |
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114 | Command (m for help): </literal><userinput>t</userinput>
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115 | <literal>Partition number (1-9, default 9): </literal><userinput>1</userinput>
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116 | <literal>Partition type or alias (type L to list all): </literal><userinput>uefi</userinput>
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117 | <literal>Changed type of partition 'Linux filesystem' to 'EFI System'.
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118 |
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119 | Command (m for help): </literal><userinput>w</userinput>
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120 | <literal>The partition table has been altered.
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121 | Calling ioctl() to re-read partition table.
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122 | Syncing disks.</literal></screen>
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123 |
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124 | <para>
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125 | Still as the <systemitem class="username">root</systemitem> user,
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126 | create a mount point for the EFI partition on the USB flash drive
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127 | and mount it:
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128 | </para>
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129 |
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130 | <screen role="nodump"><userinput>mount --mkdir -v -t vfat /dev/sdx1 -o codepage=437,iocharset=iso8859-1 \
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131 | /mnt/rescue</userinput></screen>
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132 |
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133 | <para>
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134 | Install GRUB for EFI on the partition:
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135 | </para>
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136 |
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137 | <screen role="nodump"><userinput>grub-install --target=x86_64-efi --removable \
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138 | --efi-directory=/mnt/rescue --boot-directory=/mnt/rescue</userinput></screen>
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139 |
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140 | <para>
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141 | Unmount the partition:
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142 | </para>
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143 |
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144 | <screen role="nodump"><userinput>umount /mnt/rescue</userinput></screen>
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145 |
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146 | <para>
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147 | Now the USB flash drive can be used as an emergency boot disk on any x86-64
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148 | UEFI platform. It will boot the system and show the GRUB shell. Then you
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149 | can type commands to boot your operating system from the hard drive.
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150 | To learn how to select the boot device, read the manual of your
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151 | motherboard or laptop.
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152 | </para>
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153 |
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154 | </sect2>
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155 |
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156 | <sect2>
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157 | <title>Find or Create the EFI System Partition</title>
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158 |
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159 | <para>
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160 | On EFI based systems, the bootloaders are installed in a special FAT32
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161 | partition called an <emphasis>EFI System Partition</emphasis> (ESP).
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162 | If your system supports EFI, and a recent version of some Linux
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163 | distribution or Windows is pre-installed, it's likely that the ESP
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164 | has already been created. As the
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165 | <systemitem class="username">root</systemitem> user, list all the
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166 | partitions on your hard drive (replace <userinput>sda</userinput>
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167 | with the device corresponding to the appropriate hard drive):
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168 | </para>
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169 |
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170 | <screen role="nodump"><userinput>fdisk -l /dev/sda</userinput></screen>
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171 |
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172 | <para>
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173 | The <quote>Type</quote> column of the ESP should be
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174 | <literal>EFI System</literal>.
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175 | </para>
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176 |
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177 | <para>
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178 | If the system or the hard drive is new, or it's the first
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179 | installation of a UEFI-booted OS on the system, the ESP may not exist.
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180 | In that case, install <xref linkend='dosfstools'/> first. Then create
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181 | a new partition, make a
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182 | <systemitem class="filesystem">vfat</systemitem> file system on it,
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183 | and set the partition type to <quote>EFI system</quote>. See the
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184 | instructions for the emergency boot device above as a reference.
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185 | </para>
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186 |
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187 | <warning>
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188 | <para>
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189 | Some (old) UEFI implementations may require the ESP to be the first
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190 | partition on the disk.
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191 | </para>
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192 | </warning>
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193 |
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194 | <para>
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195 | Now, as the <systemitem class="username">root</systemitem> user,
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196 | create the mount point for the ESP, and mount it (replace
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197 | <userinput>sda1</userinput> with the device node corresponding to
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198 | the ESP):
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199 | </para>
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200 |
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201 | <screen role="nodump"><userinput>mount --mkdir -v -t vfat /dev/sda1 -o codepage=437,iocharset=iso8859-1 \
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202 | /boot/efi</userinput></screen>
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203 |
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204 | <para>
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205 | If you want to mount the ESP automatically during system boot,
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206 | as the &root; user, add an entry for the ESP into
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207 | <filename>/etc/fstab</filename>:
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208 | </para>
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209 |
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210 | <screen role="nodump"><userinput>cat >> /etc/fstab << EOF</userinput>
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211 | <literal>/dev/sda1 /boot/efi vfat codepage=437,iocharset=iso8859-1 0 1</literal>
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212 | <userinput>EOF</userinput></screen>
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213 |
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214 | </sect2>
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215 |
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216 | <sect2>
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217 | <title>Minimal Boot Configuration with GRUB and EFI</title>
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218 |
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219 | <para>
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220 | On UEFI based systems, GRUB works by installing an EFI application
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221 | (a special kind of executable) into the ESP. The EFI firmware will
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222 | search boot loaders in EFI applications from boot entries recorded
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223 | in EFI variables, and additionally a hardcoded path
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224 | <filename>EFI/BOOT/BOOTX64.EFI</filename>. Normally, a boot loader
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225 | should be installed into a custom path and the path should be recorded
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226 | in the EFI variables. The use of the hardcoded path should be
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227 | avoided if possible. However, in some cases we have to use
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228 | the hardcoded path:
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229 | </para>
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230 |
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231 | <itemizedlist>
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232 | <listitem>
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233 | <para>
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234 | The system is not booted with EFI yet, making EFI variables
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235 | inaccessible.
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236 | </para>
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237 | </listitem>
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238 | <listitem>
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239 | <para>
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240 | The EFI firmware is 64-bit but the LFS system is 32-bit, making
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241 | EFI variables inaccessible because the kernel cannot invoke EFI
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242 | runtime services with a different virtual address length.
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243 | </para>
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244 | </listitem>
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245 | <listitem>
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246 | <para>
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247 | LFS is built for a Live USB, so we cannot rely on EFI variables,
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248 | which are stored in NVRAM or EEPROM on the local machine.
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249 | </para>
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250 | </listitem>
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251 | <listitem>
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252 | <para>
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253 | You are unable or unwilling to install the
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254 | <application>efibootmgr</application> for manipulating boot
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255 | entries in EFI variables.
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256 | </para>
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257 | </listitem>
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258 | </itemizedlist>
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259 |
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260 | <para>
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261 | In these cases, follow these instructions to install the GRUB EFI
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262 | application into the hardcoded path and make a minimal boot
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263 | configuration. Otherwise it's better to skip ahead and set up the
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264 | boot configuration normally.
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265 | </para>
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266 |
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267 | <para>
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268 | To install GRUB with the EFI application in the hardcoded
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269 | path <filename>EFI/BOOT/BOOTX64.EFI</filename>, first ensure the boot
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270 | partition is mounted at <filename class="directory">/boot</filename>
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271 | and the ESP is mounted at
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272 | <filename class="directory">/boot/efi</filename>. Then, as the &root;
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273 | user, run the command:
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274 | </para>
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275 |
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276 | <note>
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277 | <para>
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278 | This command will overwrite
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279 | <filename>/boot/efi/EFI/BOOT/BOOTX64.EFI</filename>. It may break a
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280 | bootloader already installed there. Back it up if you are not sure.
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281 | </para>
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282 | </note>
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283 |
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284 | <screen role="nodump"><userinput>grub-install --target=x86_64-efi --removable</userinput></screen>
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285 |
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286 | <para>
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287 | This command will install the GRUB EFI application into the hardcoded path
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288 | <filename>/boot/efi/EFI/BOOT/BOOTX64.EFI</filename>, so the EFI
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289 | firmware can find and load it. The remaining GRUB files are installed
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290 | in the <filename class="directory">/boot/grub</filename> directory and
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291 | will be loaded by <filename>BOOTX64.EFI</filename> during system boot.
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292 | </para>
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293 |
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294 | <note>
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295 | <para>
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296 | The EFI firmware usually prefers the EFI applications with a path
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297 | stored in EFI variables to the EFI
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298 | application at the hardcoded path. So you may need to invoke the
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299 | boot selection menu or firmware setting interface to select the
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300 | newly installed GRUB manually on the next boot. Read the manual of
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301 | your motherboard or laptop to learn how.
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302 | </para>
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303 | </note>
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304 |
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305 | <para>
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306 | If you've followed the instructions in this section and set up a minimal boot
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307 | configuration, now skip ahead to
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308 | <quote>Creating the GRUB Configuration File</quote>.
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309 | </para>
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310 | </sect2>
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311 |
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312 | <sect2>
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313 | <title>Mount the EFI Variable File System</title>
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314 |
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315 | <para>
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316 | The installation of GRUB on a UEFI platform requires that the EFI Variable
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317 | file system, <systemitem class="filesystem">efivarfs</systemitem>, is
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318 | mounted. As the <systemitem class="username">root</systemitem> user,
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319 | mount it if it's not already mounted:
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320 | </para>
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321 |
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322 | <screen role="nodump"><userinput>mountpoint /sys/firmware/efi/efivars || mount -v -t efivarfs efivarfs /sys/firmware/efi/efivars</userinput></screen>
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323 |
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324 | <note revision="systemd">
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325 | <para>
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326 | If the system is booted with UEFI and systemd,
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327 | <systemitem class="filesystem">efivarfs</systemitem> will be mounted
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328 | automatically. However, in the LFS chroot environment it still needs to
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329 | be mounted manually.
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330 | </para>
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331 | </note>
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332 |
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333 | <para revision="sysv">
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334 | Now add an entry for the
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335 | <systemitem class="filesystem">efivarfs</systemitem> in
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336 | <filename>/etc/fstab</filename> so it will be mounted automatically
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337 | during system boot:
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338 | </para>
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339 |
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340 | <screen revision="sysv" role="nodump"><userinput>cat >> /etc/fstab << EOF</userinput>
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341 | <literal>efivarfs /sys/firmware/efi/efivars efivarfs defaults 0 0</literal>
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342 | <userinput>EOF</userinput></screen>
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343 |
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344 | <warning>
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345 | <para>
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346 | If the system is not booted with UEFI, the directory
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347 | <filename class="directory">/sys/firmware/efi</filename> will be
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348 | missing. In this case you should boot the system in UEFI mode with
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349 | the emergency boot disk or using a minimal boot configuration created as
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350 | above, then mount
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351 | <systemitem class="filesystem">efivarfs</systemitem> and continue.
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352 | </para>
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353 | </warning>
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354 | </sect2>
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355 |
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356 | <sect2>
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357 | <title>Setting Up the Configuration</title>
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358 |
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359 | <para>
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360 | On UEFI based systems, GRUB works by installing an EFI application
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361 | (a special kind of executable) into
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362 | <filename class="directory">/boot/efi/EFI/[id]/grubx64.efi</filename>,
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363 | where <filename class="directory">/boot/efi</filename> is the mount
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364 | point of the ESP, and <literal>[id]</literal> is replaced with an
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365 | identifier specified in the <command>grub-install</command> command
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366 | line. GRUB will create an entry in the EFI variables containing
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367 | the path <literal>EFI/[id]/grubx64.efi</literal> so the EFI firmware
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368 | can find <filename>grubx64.efi</filename> and load it.
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369 | </para>
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370 |
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371 | <para>
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372 | <filename>grubx64.efi</filename> is very lightweight (136 KB with
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373 | GRUB-2.06) so it will not use much space in the ESP. A typical ESP
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374 | size is 100 MB (for Windows boot manager, which uses about 50 MB in
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375 | the ESP). Once <filename>grubx64.efi</filename> has been loaded by the
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376 | firmware, it will load GRUB modules from the boot partition.
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377 | The default location is
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378 | <filename class="directory">/boot/grub</filename>.
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379 | </para>
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380 |
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381 | <para>
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382 | As the <systemitem class="username">root</systemitem> user, install
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383 | the GRUB files into <filename>/boot/efi/EFI/LFS/grubx64.efi</filename>
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384 | and <filename class="directory">/boot/grub</filename>. Then set up the
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385 | boot entry in the EFI variables:
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386 | </para>
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387 |
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388 | <screen role="nodump"><userinput>grub-install --bootloader-id=LFS --recheck</userinput></screen>
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389 |
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390 | <para>
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391 | If the installation is successful, the output should be:
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392 | </para>
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393 |
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394 | <screen role="nodump"><literal>Installing for x86_64-efi platform.
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395 | Installation finished. No error reported.</literal></screen>
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396 |
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397 | <para>
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398 | Issue the <command>efibootmgr | cut -f 1</command> command to recheck the EFI boot
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399 | configuration. An example of the output is:
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400 | </para>
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401 |
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402 | <screen role="nodump"><literal>BootCurrent: 0000
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403 | Timeout: 1 seconds
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404 | BootOrder: 0005,0000,0002,0001,0003,0004
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405 | Boot0000* ARCH
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406 | Boot0001* UEFI:CD/DVD Drive
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407 | Boot0002* Windows Boot Manager
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408 | Boot0003* UEFI:Removable Device
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409 | Boot0004* UEFI:Network Device
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410 | Boot0005* LFS</literal></screen>
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411 |
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412 | <para>
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413 | Note that <literal>0005</literal> is the first in the
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414 | <literal>BootOrder</literal>, and <literal>Boot0005</literal>
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415 | is <literal>LFS</literal>. This means that on the next boot, the
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416 | version of GRUB installed by LFS will be used to boot the system.
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417 | </para>
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418 |
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419 | </sect2>
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420 |
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421 | <sect2>
|
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422 | <title>Creating the GRUB Configuration File</title>
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423 |
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424 | <indexterm zone="grub-setup grub-video">
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425 | <primary sortas="e-boot-grub-grub-cfg">/boot/grub/grub.cfg</primary>
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426 | </indexterm>
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427 |
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428 | <para>
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429 | Generate <filename>/boot/grub/grub.cfg</filename> to configure the
|
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430 | boot menu of GRUB:
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431 | </para>
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432 |
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433 | <screen role="nodump"><userinput>cat > /boot/grub/grub.cfg << EOF</userinput>
|
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434 | <literal># Begin /boot/grub/grub.cfg
|
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435 | set default=0
|
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436 | set timeout=5
|
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437 |
|
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438 | insmod part_gpt
|
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439 | insmod ext2
|
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440 | set root=(hd0,2)
|
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441 |
|
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442 | insmod all_video
|
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443 | if loadfont /boot/grub/fonts/unicode.pf2; then
|
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444 | terminal_output gfxterm
|
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445 | fi
|
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446 |
|
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447 | menuentry "GNU/Linux, Linux 6.4.10-lfs-12.0" {
|
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448 | linux /boot/vmlinuz-6.4.10-lfs-12.0 root=/dev/sda2 ro
|
---|
449 | }
|
---|
450 |
|
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451 | menuentry "Firmware Setup" {
|
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452 | fwsetup
|
---|
453 | }</literal>
|
---|
454 | <userinput>EOF</userinput></screen>
|
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455 |
|
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456 | <para>
|
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457 | Refer to <ulink url='&lfs-root;/chapter10/grub.html'>the LFS
|
---|
458 | book</ulink> for the basic knowledge about the
|
---|
459 | <filename>grub.cfg</filename> file.
|
---|
460 | <literal>(hd0,2)</literal>, <literal>sda2</literal>, and
|
---|
461 | <literal>6.4.10-lfs-12.0</literal> must match your
|
---|
462 | configuration.
|
---|
463 | </para>
|
---|
464 |
|
---|
465 | <para>
|
---|
466 | The <command>insmod all_video</command> directive loads various
|
---|
467 | modules for video support. It's needed to initialize the EFI
|
---|
468 | framebuffer for the kernel to print messages correctly before the
|
---|
469 | kernel GPU driver initialization.
|
---|
470 | </para>
|
---|
471 |
|
---|
472 | <para>
|
---|
473 | The <command>terminal_output gfxterm</command> directive changes
|
---|
474 | the display resolution of the GRUB menu to match your display device.
|
---|
475 | It will break the rendering if the <filename>unicode.pf2</filename>
|
---|
476 | font data file is not loaded, so it's guarded by a
|
---|
477 | <command>if</command> directive.
|
---|
478 | </para>
|
---|
479 |
|
---|
480 | <note>
|
---|
481 | <para>
|
---|
482 | From GRUB's perspective, the files are relative to the partitions
|
---|
483 | used. If you used a separate /boot partition, remove /boot from the
|
---|
484 | above paths (to kernel and to <filename>unicode.pf2</filename>). You
|
---|
485 | will also need to change the "set root" line to point to the boot
|
---|
486 | partition.
|
---|
487 | </para>
|
---|
488 | </note>
|
---|
489 |
|
---|
490 | <para>
|
---|
491 | The <literal>Firmware Setup</literal> entry can be used to enter the
|
---|
492 | configuration interface provided by the firmware (sometimes called
|
---|
493 | <quote>BIOS configuration</quote>).
|
---|
494 | </para>
|
---|
495 | </sect2>
|
---|
496 |
|
---|
497 | <sect2>
|
---|
498 | <title>Dual-booting with Windows</title>
|
---|
499 |
|
---|
500 | <para>
|
---|
501 | Add a menu entry for Windows into <filename>grub.cfg</filename>:
|
---|
502 | </para>
|
---|
503 |
|
---|
504 | <screen role="nodump"><userinput>cat >> /boot/grub/grub.cfg << EOF</userinput>
|
---|
505 | <literal># Begin Windows addition
|
---|
506 |
|
---|
507 | menuentry "Windows 11" {
|
---|
508 | insmod fat
|
---|
509 | insmod chain
|
---|
510 | set root=(hd0,1)
|
---|
511 | chainloader /EFI/Microsoft/Boot/bootmgfw.efi
|
---|
512 | }</literal>
|
---|
513 | <userinput>EOF</userinput></screen>
|
---|
514 |
|
---|
515 | <para>
|
---|
516 | <literal>(hd0,1)</literal> should be replaced with the GRUB
|
---|
517 | designated name for the ESP. The <literal>chainloader</literal>
|
---|
518 | directive can be used to tell GRUB to run another EFI executable,
|
---|
519 | in this case the Windows Boot Manager. You may put more usable tools
|
---|
520 | in EFI executable format (for example, an EFI shell) into the ESP and
|
---|
521 | create GRUB entries for them, as well.
|
---|
522 | </para>
|
---|
523 |
|
---|
524 | </sect2>
|
---|
525 |
|
---|
526 | </sect1>
|
---|