You cannot boot two kernels at once, mention the "unload" command.

PR:		130482
Submitted by:	Ben Kaduk <kaduk@mit.edu>

en_US.ISO8859-1/books/handbook/boot/chapter.sgml

@@ -343,7 +343,10 @@ boot:</screen>
 	  <listitem>
 	    <para>Immediately proceeds to boot the kernel, with the
 	      given options, if any, and with the kernel name given,
-	      if it is.</para>
+	      if it is.  Providing a kernel name on the command-line
+	      is only applicable after an <emphasis>unload</emphasis>
+	      command has been issued, otherwise the previously-loaded
+	      kernel will be used.</para>
 	  </listitem>
 	</varlistentry>