diff --git a/Marlin/Configuration.h b/Marlin/Configuration.h
index be968b9476..cb40ea6f79 100644
--- a/Marlin/Configuration.h
+++ b/Marlin/Configuration.h
@@ -24,6 +24,9 @@
  // If you have a trex 3, stock is this option plus 2208 on all axis. None in spreadcycle.
 #define TREX3
 
+// If you have a trex 3 that was upgraded from a 2+ with the kit, modifies home position and offsets.
+//#define TREX3_UPGRADE
+
 //#define X_2208
 //#define X_Spreadcycle
 //#define X_S109
@@ -39,7 +42,7 @@
 
 #define BedAC
 
-#define tallVersion
+//#define tallVersion
 
 /*
  * Enables a filament sensor plugged into the laser pin. Disables the laser
@@ -50,6 +53,11 @@
 
 //////////////////////////////////DO not edit below here unless you know what youre doing!  //////////////////////////////////
 
+// The TREX2+ upgraded to the 3 enables most of the same options, simplify here
+#if ENABLED(TREX3_UPGRADED_FROM_2_PLUS)
+  #define TREX3
+#endif
+
 #if ENABLED(TREX3)
   #if DISABLED(X_S109)
     #define X_2208
@@ -184,7 +192,9 @@
 
 // Optional custom name for your RepStrap or other custom machine
 // Displayed in the LCD "Ready" message
-#if ENABLED(TREX3)
+#if ENABLED(TREX3_UPGRADE)
+  #define CUSTOM_MACHINE_TIME "T-REX 3(u)"
+#elif ENABLED(TREX3)
   #define CUSTOM_MACHINE_NAME "T-REX 3"
 #else
   #define CUSTOM_MACHINE_NAME "T-REX 2+"
@@ -1133,11 +1143,19 @@
 #define Y_BED_SIZE 400
 
 // Travel limits (mm) after homing, corresponding to endstop positions.
-#define X_MIN_POS -47
-#define Y_MIN_POS 0
-#define Z_MIN_POS 0
-#define X_MAX_POS 460
-#define Y_MAX_POS Y_BED_SIZE
+#if DISABLED(TREX3) || ENABLED(TREX3_UPGRADE)
+    #define X_MIN_POS -42
+    #define Y_MIN_POS 0
+    #define Z_MIN_POS 0
+    #define X_MAX_POS 450
+    #define Y_MAX_POS Y_BED_SIZE
+#else ENABLED(TREX3)
+    #define X_MIN_POS -47
+    #define Y_MIN_POS 0
+    #define Z_MIN_POS 0
+    #define X_MAX_POS 460
+    #define Y_MAX_POS Y_BED_SIZE
+#endif
 #if(ENABLED(tallVersion))
   #define Z_MAX_POS 700
 #else
@@ -1197,9 +1215,7 @@
  #endif
   #define FIL_RUNOUT_PULLUP          // Use internal pullup for filament runout pins.
   //#define FIL_RUNOUT_PULLDOWN      // Use internal pulldown for filament runout pins.
-  #if DISABLED(TREX3)
-    #define FIL_RUNOUT_PIN 4
-  #endif
+
   // Set one or more commands to execute on filament runout.
   // (After 'M412 H' Marlin will ask the host to handle the process.)
   #define FILAMENT_RUNOUT_SCRIPT "M600"