diff --git a/Marlin/pins_5DPRINT.h b/Marlin/pins_5DPRINT.h
index 9bb67ecb9..21769a50b 100644
--- a/Marlin/pins_5DPRINT.h
+++ b/Marlin/pins_5DPRINT.h
@@ -33,6 +33,7 @@
 #define DEFAULT_MACHINE_NAME "Makibox"
 #define BOARD_NAME           "5DPrint D8"
 
+#define USBCON 1286  // Disable MarlinSerial etc.
 #define LARGE_FLASH        true
 
 //
diff --git a/Marlin/pins_BRAINWAVE.h b/Marlin/pins_BRAINWAVE.h
index a1006aec0..625471341 100644
--- a/Marlin/pins_BRAINWAVE.h
+++ b/Marlin/pins_BRAINWAVE.h
@@ -33,6 +33,8 @@
 
 #define BOARD_NAME         "Brainwave"
 
+#define USBCON 646  // Disable MarlinSerial etc.
+
 //
 // Limit Switches
 //
diff --git a/Marlin/pins_BRAINWAVE_PRO.h b/Marlin/pins_BRAINWAVE_PRO.h
index f263f1bc6..40f589b07 100644
--- a/Marlin/pins_BRAINWAVE_PRO.h
+++ b/Marlin/pins_BRAINWAVE_PRO.h
@@ -39,6 +39,7 @@
 
 #define BOARD_NAME         "Brainwave Pro"
 
+#define USBCON 1286  // Disable MarlinSerial etc.
 #define LARGE_FLASH        true
 
 //
diff --git a/Marlin/pins_PRINTRBOARD.h b/Marlin/pins_PRINTRBOARD.h
index fb1874b64..f2a2bbb0f 100644
--- a/Marlin/pins_PRINTRBOARD.h
+++ b/Marlin/pins_PRINTRBOARD.h
@@ -36,6 +36,8 @@
 #endif
 
 #define BOARD_NAME         "Printrboard"
+
+#define USBCON 1286  // Disable MarlinSerial etc.
 #define LARGE_FLASH        true
 
 // Disable JTAG pins so they can be used for the Extrudrboard
diff --git a/Marlin/pins_SAV_MKI.h b/Marlin/pins_SAV_MKI.h
index 530f63ada..e3e24c925 100644
--- a/Marlin/pins_SAV_MKI.h
+++ b/Marlin/pins_SAV_MKI.h
@@ -35,6 +35,7 @@
 #define DEFAULT_SOURCE_CODE_URL "https://github.com/fmalpartida/Marlin/tree/SAV-MkI-config"
 #define BOARD_NAME              "SAV MkI"
 
+#define USBCON 1286  // Disable MarlinSerial etc.
 #define LARGE_FLASH        true
 
 #define X_STEP_PIN         0
diff --git a/Marlin/pins_TEENSY2.h b/Marlin/pins_TEENSY2.h
index bfadf295d..65992beec 100644
--- a/Marlin/pins_TEENSY2.h
+++ b/Marlin/pins_TEENSY2.h
@@ -76,6 +76,7 @@
 
 #define BOARD_NAME         "Teensy++2.0"
 
+#define USBCON 1286  // Disable MarlinSerial etc.
 #define LARGE_FLASH        true
 
 #define X_STEP_PIN         28 //  0 Marlin
diff --git a/Marlin/pins_TEENSYLU.h b/Marlin/pins_TEENSYLU.h
index 775837767..2269b3157 100644
--- a/Marlin/pins_TEENSYLU.h
+++ b/Marlin/pins_TEENSYLU.h
@@ -37,6 +37,7 @@
 
 #define BOARD_NAME         "Teensylu"
 
+#define USBCON 1286  // Disable MarlinSerial etc.
 #define LARGE_FLASH        true
 
 #define X_STEP_PIN          0