diff --git a/Marlin/src/pins/linux/pins_RAMPS_LINUX.h b/Marlin/src/pins/linux/pins_RAMPS_LINUX.h
index 2cb6fb597..d21c487e5 100644
--- a/Marlin/src/pins/linux/pins_RAMPS_LINUX.h
+++ b/Marlin/src/pins/linux/pins_RAMPS_LINUX.h
@@ -363,6 +363,24 @@
   #ifndef E4_SERIAL_RX_PIN
     #define E4_SERIAL_RX_PIN -1
   #endif
+  #ifndef E5_SERIAL_TX_PIN
+    #define E5_SERIAL_TX_PIN -1
+  #endif
+  #ifndef E5_SERIAL_RX_PIN
+    #define E5_SERIAL_RX_PIN -1
+  #endif
+  #ifndef E6_SERIAL_TX_PIN
+    #define E6_SERIAL_TX_PIN -1
+  #endif
+  #ifndef E6_SERIAL_RX_PIN
+    #define E6_SERIAL_RX_PIN -1
+  #endif
+  #ifndef E7_SERIAL_TX_PIN
+    #define E7_SERIAL_TX_PIN -1
+  #endif
+  #ifndef E7_SERIAL_RX_PIN
+    #define E7_SERIAL_RX_PIN -1
+  #endif
 #endif
 
 //////////////////////////
diff --git a/Marlin/src/pins/ramps/pins_RAMPS.h b/Marlin/src/pins/ramps/pins_RAMPS.h
index f6ccff24f..b7e9df475 100644
--- a/Marlin/src/pins/ramps/pins_RAMPS.h
+++ b/Marlin/src/pins/ramps/pins_RAMPS.h
@@ -390,6 +390,24 @@
   #ifndef E4_SERIAL_RX_PIN
     #define E4_SERIAL_RX_PIN -1
   #endif
+  #ifndef E5_SERIAL_TX_PIN
+    #define E5_SERIAL_TX_PIN -1
+  #endif
+  #ifndef E5_SERIAL_RX_PIN
+    #define E5_SERIAL_RX_PIN -1
+  #endif
+  #ifndef E6_SERIAL_TX_PIN
+    #define E6_SERIAL_TX_PIN -1
+  #endif
+  #ifndef E6_SERIAL_RX_PIN
+    #define E6_SERIAL_RX_PIN -1
+  #endif
+  #ifndef E7_SERIAL_TX_PIN
+    #define E7_SERIAL_TX_PIN -1
+  #endif
+  #ifndef E7_SERIAL_RX_PIN
+    #define E7_SERIAL_RX_PIN -1
+  #endif
 #endif
 
 //
diff --git a/Marlin/src/pins/ramps/pins_TT_OSCAR.h b/Marlin/src/pins/ramps/pins_TT_OSCAR.h
index 1c40729a8..145817b48 100644
--- a/Marlin/src/pins/ramps/pins_TT_OSCAR.h
+++ b/Marlin/src/pins/ramps/pins_TT_OSCAR.h
@@ -147,6 +147,9 @@
   #define E3_SERIAL_RX_PIN -1
   #define E4_SERIAL_TX_PIN -1
   #define E4_SERIAL_RX_PIN -1
+  #define E5_SERIAL_RX_PIN -1
+  #define E6_SERIAL_RX_PIN -1
+  #define E7_SERIAL_RX_PIN -1
 #endif
 
 //
diff --git a/Marlin/src/pins/ramps/pins_Z_BOLT_X_SERIES.h b/Marlin/src/pins/ramps/pins_Z_BOLT_X_SERIES.h
index 8545dc488..d94f5e44c 100644
--- a/Marlin/src/pins/ramps/pins_Z_BOLT_X_SERIES.h
+++ b/Marlin/src/pins/ramps/pins_Z_BOLT_X_SERIES.h
@@ -285,4 +285,22 @@
   #ifndef E4_SERIAL_RX_PIN
     #define E4_SERIAL_RX_PIN -1
   #endif
+  #ifndef E5_SERIAL_TX_PIN
+    #define E5_SERIAL_TX_PIN -1
+  #endif
+  #ifndef E5_SERIAL_RX_PIN
+    #define E5_SERIAL_RX_PIN -1
+  #endif
+  #ifndef E6_SERIAL_TX_PIN
+    #define E6_SERIAL_TX_PIN -1
+  #endif
+  #ifndef E6_SERIAL_RX_PIN
+    #define E6_SERIAL_RX_PIN -1
+  #endif
+  #ifndef E7_SERIAL_TX_PIN
+    #define E7_SERIAL_TX_PIN -1
+  #endif
+  #ifndef E7_SERIAL_RX_PIN
+    #define E7_SERIAL_RX_PIN -1
+  #endif
 #endif