diff --git a/documentation/ref-manual/ref-variables.xml b/documentation/ref-manual/ref-variables.xml
index 897522ab2e..ffc40c98ae 100644
--- a/documentation/ref-manual/ref-variables.xml
+++ b/documentation/ref-manual/ref-variables.xml
@@ -1979,6 +1979,16 @@ Core layer for images cannot be removed
+ IMAGE_ROOTFS
+
+
+ The location of the root filesystem.
+ This variable is not configurable.
+ Do not change it.
+
+
+
+