diff --git a/en_US.ISO8859-1/books/porters-handbook/uses.xml b/en_US.ISO8859-1/books/porters-handbook/uses.xml
index 633765519f..3d263d22ce 100644
--- a/en_US.ISO8859-1/books/porters-handbook/uses.xml
+++ b/en_US.ISO8859-1/books/porters-handbook/uses.xml
@@ -144,7 +144,13 @@
     <listitem><para>Define <varname>KMODDIR</varname> to <filename
 	class="directory">/boot/modules</filename> by default, add it
       to <varname>PLIST_SUB</varname> and <varname>MAKE_ENV</varname>,
-      and create it upon installation.</para></listitem>
+      and create it upon installation.  If KMODDIR is set to
+      <filename class="directory">/boot/kernel</filename>, it will be
+      rewritten to <filename class="directory">/boot/modules</filename>.
+      This prevents breaking packages when upgrading the kernel due to
+      <filename class="directory">/boot/kernel</filename> being renamed
+      to <filename class="directory">/boot/kernel.old</filename> in the
+      process.</para></listitem>
     <listitem><para>Handle cross-referencing kernel modules upon installation
       and deinstallation.</para></listitem>
   </itemizedlist>