diff --git a/documentation/ref-manual/ref-classes.xml b/documentation/ref-manual/ref-classes.xml
index c1c3baa392..ce8f6a6ba2 100644
--- a/documentation/ref-manual/ref-classes.xml
+++ b/documentation/ref-manual/ref-classes.xml
@@ -256,6 +256,45 @@
     </para>
 </section>
 
+<section id='ref-classes-bootimg.bbclass'>
+    <title><filename>bootimg.bbclass</filename></title>
+
+    <para>
+        The boot image (<filename>bootimg</filename> class creates a bootable
+        image using SYSLINUX, your kernel and an optional initial ram disk
+        (<filename>initrd</filename>).
+    </para>
+
+    <para>
+        When you use this class, two things happen:
+        <itemizedlist>
+            <listitem><para>
+                A <filename>.hddimg</filename> file is created.
+                This file which is an MSDOS filesystem that contains SYSLINUX,
+                a kernel, an <filename>initrd</filename>, and a root filesystem
+                image.
+                All three of these can be written to hard drives directly and
+                also booted on a USB flash disks using <filename>dd</filename>.
+                </para></listitem>
+            <listitem><para>
+                A CD <filename>.iso</filename> image is created.
+                When this file is booted, the <filename>initrd</filename>
+                boots and processes the label selected in SYSLINUX.
+                Actions based on the label are then performed (e.g. installing
+                to a hard drive).</para></listitem>
+        </itemizedlist>
+    </para>
+
+    <para>
+        The <filename>bootimg</filename> class supports the
+        <link linkend='var-INITRD'><filename>INITRD</filename></link>,
+        <link linkend='var-NOISO'><filename>NOISO</filename></link>,
+        <link linkend='var-NOHDD'><filename>NOHDD</filename></link>, and
+        <link linkend='var-ROOTFS'><filename>ROOTFS</filename></link>
+        variables.
+    </para>
+</section>
+
 <section id='ref-classes-debian'>
     <title>Debian Renaming - <filename>debian.bbclass</filename></title>