diff --git a/Documentation/NuttxPortingGuide.html b/Documentation/NuttxPortingGuide.html
index 893888bee68..a209146e22e 100644
--- a/Documentation/NuttxPortingGuide.html
+++ b/Documentation/NuttxPortingGuide.html
@@ -1123,6 +1123,8 @@ The system can be re-made subsequently by just typing <code>make</code>.
      the particular chip or SoC.</li>
   <li><code>CONFIG_ARCH_BOARD_name</code>:
      For use in C code</li>
+  <li><code>CONFIG_ENDIAN_BIG</code>:
+     Define if big endian (default is little endian).</li>
 </ul>
 
 <p>