diff --git a/src/boards/bluemicro/board.h b/src/boards/bluemicro/board.h
index 29b83b1..df4a1ec 100644
--- a/src/boards/bluemicro/board.h
+++ b/src/boards/bluemicro/board.h
@@ -40,7 +40,7 @@
  *------------------------------------------------------------------*/
 #define BUTTONS_NUMBER    2                 // none connected at all
 #define BUTTON_1          _PINNUM(0, 18)    // unusable: RESET
-#define BUTTON_2          _PINNUM(1, 1)     // no connection
+#define BUTTON_2          _PINNUM(1, 1)     // no connection on E73-2G4M08S1C Module
 #define BUTTON_PULL       NRF_GPIO_PIN_PULLUP
 
 //--------------------------------------------------------------------+