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<table class="head">
<tr>
<td class="head-ltitle">UEFI(8)</td>
<td class="head-vol">System Manager's Manual</td>
<td class="head-rtitle">UEFI(8)</td>
</tr>
</table>
<div class="manual-text">
<section class="Sh">
<h1 class="Sh" id="NAME"><a class="permalink" href="#NAME">NAME</a></h1>
<p class="Pp"><code class="Nm">UEFI</code> — <span class="Nd">Unified
Extensible Firmware Interface bootstrapping procedures</span></p>
</section>
<section class="Sh">
<h1 class="Sh" id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">DESCRIPTION</a></h1>
<p class="Pp">The <code class="Nm">UEFI</code> Unified Extensible Firmware
Interface provides boot- and run-time services to operating systems.
<code class="Nm">UEFI</code> is a replacement for the legacy BIOS on the
i386 and amd64 CPU architectures, and is also used on arm, arm64 and riscv
architectures.</p>
<p class="Pp">The UEFI specification is the successor to the Extensible Firmware
Interface (EFI) specification. The terms UEFI and EFI are often used
interchangeably.</p>
<p class="Pp">The <code class="Nm">UEFI</code> boot process loads system
bootstrap code located in an EFI System Partition (ESP). The ESP is a GPT or
MBR partition with a specific identifier that contains an
<a class="Xr">msdosfs(4)</a> FAT file system with a specified file
hierarchy.</p>
<table class="Bl-column Bd-indent">
<tr id="Partition">
<td><a class="permalink" href="#Partition"><b class="Sy">Partition
Scheme</b></a></td>
<td><a class="permalink" href="#ESP"><b class="Sy" id="ESP">ESP
Identifier</b></a></td>
</tr>
<tr>
<td>GPT</td>
<td>C12A7328-F81F-11D2-BA4B-00A0C93EC93B</td>
</tr>
<tr>
<td>MBR</td>
<td>0xEF</td>
</tr>
</table>
<p class="Pp">The <code class="Nm">UEFI</code> boot process proceeds as
follows:</p>
<ol class="Bl-enum Bd-indent Bl-compact">
<li><code class="Nm">UEFI</code> firmware runs at power up and searches for an
OS loader in the EFI system partition. The path to the loader may be set
by an EFI environment variable managed by <a class="Xr">efibootmgr(8)</a>.
If not set, an architecture-specific default is used.
<table class="Bl-column Bd-indent">
<tr id="Architecture">
<td><a class="permalink" href="#Architecture"><b class="Sy">Architecture</b></a></td>
<td><a class="permalink" href="#Default"><b class="Sy" id="Default">Default
Path</b></a></td>
</tr>
<tr>
<td>amd64</td>
<td><span class="Pa">/EFI/BOOT/BOOTX64.EFI</span></td>
</tr>
<tr>
<td>arm</td>
<td><span class="Pa">/EFI/BOOT/BOOTARM.EFI</span></td>
</tr>
<tr>
<td>arm64</td>
<td><span class="Pa">/EFI/BOOT/BOOTAA64.EFI</span></td>
</tr>
<tr>
<td>i386</td>
<td><span class="Pa">/EFI/BOOT/BOOTIA32.EFI</span></td>
</tr>
<tr>
<td>riscv</td>
<td><span class="Pa">/EFI/BOOT/BOOTRISCV64.EFI</span></td>
</tr>
</table>
<p class="Pp">The default <code class="Nm">UEFI</code> boot configuration
for <span class="Ux">FreeBSD</span> installs
<span class="Pa">loader.efi</span> in the default path.</p>
</li>
<li><span class="Pa">loader.efi</span> reads boot configuration from
<span class="Pa">/boot.config</span> or
<span class="Pa">/boot/config</span>.</li>
<li><span class="Pa">loader.efi</span> loads and boots the kernel, as
described in <a class="Xr">loader.efi(8)</a>.</li>
</ol>
<p class="Pp">The <a class="Xr">vt(4)</a> system console is automatically
selected when booting via <code class="Nm">UEFI</code>.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="FILES"><a class="permalink" href="#FILES">FILES</a></h1>
<p class="Pp"><code class="Nm">UEFI</code> bootstrap</p>
<dl class="Bl-tag Bl-compact">
<dt><span class="Pa">/boot/loader.efi</span></dt>
<dd>Final stage bootstrap</dd>
<dt><span class="Pa">/boot/kernel/kernel</span></dt>
<dd>Default kernel</dd>
<dt><span class="Pa">/boot/kernel.old/kernel</span></dt>
<dd>Typical non-default kernel (optional)</dd>
</dl>
</section>
<section class="Sh">
<h1 class="Sh" id="SEE_ALSO"><a class="permalink" href="#SEE_ALSO">SEE
ALSO</a></h1>
<p class="Pp"><a class="Xr">msdosfs(4)</a>, <a class="Xr">vt(4)</a>,
<a class="Xr">boot.config(5)</a>, <a class="Xr">boot(8)</a>,
<a class="Xr">efibootmgr(8)</a>, <a class="Xr">efidp(8)</a>,
<a class="Xr">efivar(8)</a>, <a class="Xr">gpart(8)</a>,
<a class="Xr">loader.efi(8)</a>, <a class="Xr">uefisign(8)</a></p>
</section>
<section class="Sh">
<h1 class="Sh" id="HISTORY"><a class="permalink" href="#HISTORY">HISTORY</a></h1>
<p class="Pp">EFI boot support for the ia64 architecture first appeared in
<span class="Ux">FreeBSD 5.0</span>. <code class="Nm">UEFI</code> boot
support for amd64 first appeared in <span class="Ux">FreeBSD 10.1</span>;
for arm64 in <span class="Ux">FreeBSD 11.0</span>; for armv7 in
<span class="Ux">FreeBSD 12.0</span>; and for riscv in
<span class="Ux">FreeBSD 13.0</span>.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="BUGS"><a class="permalink" href="#BUGS">BUGS</a></h1>
<p class="Pp">There is no support for 32-bit i386 booting via UEFI.</p>
</section>
</div>
<table class="foot">
<tr>
<td class="foot-date">August 31, 2023</td>
<td class="foot-os">FreeBSD 15.0</td>
</tr>
</table>
|
