Cleaner failure of UBL without EEPROM

Marlin/Marlin_main.cpp

@@ -8866,8 +8866,11 @@ void quickstop_stepper() {
   inline void gcode_M420() {
 
     #if ENABLED(AUTO_BED_LEVELING_UBL)
+
       // L to load a mesh from the EEPROM
       if (parser.seen('L')) {
+
+        #if ENABLED(EEPROM_SETTINGS)
           const int8_t storage_slot = parser.has_value() ? parser.value_int() : ubl.state.storage_slot;
           const int16_t a = settings.calc_num_meshes();
 
@@ -8884,7 +8887,22 @@ void quickstop_stepper() {
 
           settings.load_mesh(storage_slot);
           ubl.state.storage_slot = storage_slot;
+
+        #else
+
+          SERIAL_PROTOCOLLNPGM("?EEPROM storage not available.");
+          return;
+
+        #endif
       }
+
+      // L to load a mesh from the EEPROM
+      if (parser.seen('L') || parser.seen('V')) {
+        ubl.display_map(0);  // Currently only supports one map type
+        SERIAL_ECHOLNPAIR("UBL_MESH_VALID = ", UBL_MESH_VALID);
+        SERIAL_ECHOLNPAIR("ubl.state.storage_slot = ", ubl.state.storage_slot);
+      }
+
     #endif // AUTO_BED_LEVELING_UBL
 
     // V to print the matrix or mesh
@@ -8906,15 +8924,6 @@ void quickstop_stepper() {
       #endif
     }
 
-    #if ENABLED(AUTO_BED_LEVELING_UBL)
-      // L to load a mesh from the EEPROM
-      if (parser.seen('L') || parser.seen('V')) {
-        ubl.display_map(0);  // Currently only supports one map type
-        SERIAL_ECHOLNPAIR("UBL_MESH_VALID = ", UBL_MESH_VALID);
-        SERIAL_ECHOLNPAIR("ubl.state.storage_slot = ", ubl.state.storage_slot);
-      }
-    #endif
-
     bool to_enable = false;
     if (parser.seen('S')) {
       to_enable = parser.value_bool();