diff --git a/arduino-mk-vars.md b/arduino-mk-vars.md
index c49201a..9a925e0 100644
--- a/arduino-mk-vars.md
+++ b/arduino-mk-vars.md
@@ -281,7 +281,7 @@ BOARD_TAG = uno or mega2560
 
 **Description:**
 
-1.5+ submenu as listed in `boards.txt`
+1.5+ submenu as listed in `boards.txt` or `make show_submenu`.
 
 **Example:**