diff --git a/Marlin/src/config/examples/STM32F4/Configuration.h b/Marlin/src/config/examples/STM32F4/Configuration.h
index 785f76d48..948747127 100644
--- a/Marlin/src/config/examples/STM32F4/Configuration.h
+++ b/Marlin/src/config/examples/STM32F4/Configuration.h
@@ -114,7 +114,7 @@
  *
  * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
-////#define SERIAL_PORT_2 -1
+//#define SERIAL_PORT_2 -1
 
 /**
  * This setting determines the communication speed of the printer.