diff --git a/documentation/ref-manual/ref-variables.xml b/documentation/ref-manual/ref-variables.xml
index c7db5bea58..966f7c2663 100644
--- a/documentation/ref-manual/ref-variables.xml
+++ b/documentation/ref-manual/ref-variables.xml
@@ -3200,7 +3200,7 @@
                     by default:
                     <literallayout class='monospaced'>
      jffs2
-     sum.jffs2
+     jffs2.sum
      cramfs
      ext2
      ext2.gz