diff --git a/documentation/ref-manual/ref-variables.xml b/documentation/ref-manual/ref-variables.xml
index e0ceb43f21..de7b050225 100644
--- a/documentation/ref-manual/ref-variables.xml
+++ b/documentation/ref-manual/ref-variables.xml
@@ -3637,6 +3637,19 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3"
             </glossdef>
         </glossentry>
 
+        <glossentry id='var-SERIAL_CONSOLES_CHECK'><glossterm>SERIAL_CONSOLES_CHECK</glossterm>
+            <glossdef>
+                <para>
+                    Similar to
+                    <link linkend='var-SERIAL_CONSOLES'><filename>SERIAL_CONSOLES</filename></link>
+                    except the device is checked for existence before attempting
+                    to enable it.
+                    This variable is currently only supported with SysVinit
+                    (i.e. not with systemd).
+                </para>
+            </glossdef>
+        </glossentry>
+
         <glossentry id='var-SIGGEN_EXCLUDERECIPES_ABISAFE'><glossterm>SIGGEN_EXCLUDERECIPES_ABISAFE</glossterm>
             <glossdef>
                 <para>