diff --git a/Firmware/Marlin.h b/Firmware/Marlin.h
index c0af3f07f..13f6d95c7 100644
--- a/Firmware/Marlin.h
+++ b/Firmware/Marlin.h
@@ -299,6 +299,7 @@ extern unsigned int heating_status_counter;
 extern bool custom_message;
 extern unsigned int custom_message_type;
 extern unsigned int custom_message_state;
+extern char snmm_filaments_used;
 extern unsigned long PingTime;
 
 
diff --git a/Firmware/Marlin_main.cpp b/Firmware/Marlin_main.cpp
index 8002c1d9d..ae1a3202d 100644
--- a/Firmware/Marlin_main.cpp
+++ b/Firmware/Marlin_main.cpp
@@ -285,6 +285,7 @@ bool custom_message;
 bool loading_flag = false;
 unsigned int custom_message_type;
 unsigned int custom_message_state;
+char snmm_filaments_used = 0;
 
 bool volumetric_enabled = false;
 float filament_size[EXTRUDERS] = { DEFAULT_NOMINAL_FILAMENT_DIA
@@ -4301,6 +4302,7 @@ Sigma_Exit:
           #endif
         }
       }
+	  snmm_filaments_used = 0;
       break;
     case 85: // M85
       if(code_seen('S')) {
@@ -4451,7 +4453,7 @@ Sigma_Exit:
         tmp_extruder = active_extruder;
         if(code_seen('T')) {
           tmp_extruder = code_value();
-          if(tmp_extruder >= EXTRUDERS) {
+		  if(tmp_extruder >= EXTRUDERS) {
             SERIAL_ECHO_START;
             SERIAL_ECHO(MSG_M200_INVALID_EXTRUDER);
             break;
@@ -5441,7 +5443,12 @@ case 404:  //M404 Enter the nominal filament width (3mm, 1.75mm ) N<3.0> or disp
 	case 702:
 	{
 #ifdef SNMM
-		extr_unload_all();
+		if (code_seen('U')) {
+			extr_unload_used();
+		}
+		else {
+			extr_unload_all();
+		}
 #else
 		custom_message = true;
 		custom_message_type = 2;
@@ -5479,6 +5486,7 @@ case 404:  //M404 Enter the nominal filament width (3mm, 1.75mm ) N<3.0> or disp
 	  }
 	  else {
 		  tmp_extruder = code_value();
+		  snmm_filaments_used |= (1 << tmp_extruder); //for stop print
 #ifdef SNMM
 		  snmm_extruder = tmp_extruder;
 
diff --git a/Firmware/ultralcd.cpp b/Firmware/ultralcd.cpp
index 4a82e2e62..57cb19738 100644
--- a/Firmware/ultralcd.cpp
+++ b/Firmware/ultralcd.cpp
@@ -671,7 +671,7 @@ void lcd_commands()
 			lcd_commands_step = 5;
 		}
 		if (lcd_commands_step == 7 && !blocks_queued()) {
-			enquecommand_P(PSTR("M702"));
+			enquecommand_P(PSTR("M702 U"));
 			lcd_commands_step = 3;
 		}
 	}
@@ -3254,6 +3254,30 @@ void extr_unload_all() {
 	}
 }
 
+//unloading just used filament (for snmm)
+
+void extr_unload_used() {
+	if (degHotend0() > EXTRUDE_MINTEMP) {
+		for (int i = 0; i < 4; i++) {
+			if (snmm_filaments_used & (1 << i)) {
+				change_extr(i);
+				extr_unload();
+			}
+		}
+		snmm_filaments_used = 0;
+	}
+	else {
+		lcd_implementation_clear();
+		lcd.setCursor(0, 0);
+		lcd_printPGM(MSG_ERROR);
+		lcd.setCursor(0, 2);
+		lcd_printPGM(MSG_PREHEAT_NOZZLE);
+		delay(2000);
+		lcd_implementation_clear();
+		lcd_return_to_status();
+	}
+}
+
 
 
 static void extr_unload_0() {
diff --git a/Firmware/ultralcd.h b/Firmware/ultralcd.h
index 850dad35d..cb5aa9060 100644
--- a/Firmware/ultralcd.h
+++ b/Firmware/ultralcd.h
@@ -222,9 +222,11 @@ static void extr_unload_1();
 static void extr_unload_2();
 static void extr_unload_3();
 static void lcd_disable_farm_mode();
-void extr_unload_all();
+void extr_unload_all(); 
+void extr_unload_used();
 static void extr_unload();
 
+
 void stack_error();
 static void lcd_ping_allert();
 void lcd_printer_connected();