diff --git a/firmware/marlin2.0 for Ender3/Marlin/Configuration.h b/firmware/marlin2.0 for Ender3/Marlin/Configuration.h
index 5acbb081..b2265141 100644
--- a/firmware/marlin2.0 for Ender3/Marlin/Configuration.h	
+++ b/firmware/marlin2.0 for Ender3/Marlin/Configuration.h	
@@ -110,7 +110,7 @@
  * Select a secondary serial port on the board to use for communication with the host.
  * :[-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.