diff --git a/src/slic3r/GUI/DeviceManager.cpp b/src/slic3r/GUI/DeviceManager.cpp
index 1ffc8589c..cc289c1c1 100644
--- a/src/slic3r/GUI/DeviceManager.cpp
+++ b/src/slic3r/GUI/DeviceManager.cpp
@@ -2037,6 +2037,8 @@ int MachineObject::command_set_chamber(int temp)
 
 int MachineObject::command_ams_switch(int tray_index, int old_temp, int new_temp)
 {
+    assert(!is_enable_np);
+
     BOOST_LOG_TRIVIAL(trace) << "ams_switch to " << tray_index << " with temp: " << old_temp << ", " << new_temp;
     if (old_temp < 0) old_temp = FILAMENT_DEF_TEMP;
     if (new_temp < 0) new_temp = FILAMENT_DEF_TEMP;
@@ -2077,16 +2079,28 @@ int MachineObject::command_ams_change_filament(int tray_id, int old_temp, int ne
     return this->publish_json(j.dump());
 }
 
-int MachineObject::command_ams_change_filament2(int ams_id, int slot_id, int old_temp, int new_temp)
+int MachineObject::command_ams_change_filament2(bool load_or_unload, int ams_id, int slot_id, int old_temp, int new_temp)
 {
+    assert(is_enable_np);
+
     json j;
     j["print"]["command"]     = "ams_change_filament";
     j["print"]["sequence_id"] = std::to_string(MachineObject::m_sequence_id++);
-    j["print"]["target"]      = ams_id == VIRTUAL_TRAY_MAIN_ID?VIRTUAL_TRAY_DEPUTY_ID:slot_id;
+    //j["print"]["target"]      = ams_id == VIRTUAL_TRAY_MAIN_ID?VIRTUAL_TRAY_DEPUTY_ID:slot_id; /*this is not used in new protocol*/
     j["print"]["curr_temp"]   = old_temp;
     j["print"]["tar_temp"]    = new_temp;
     j["print"]["ams_id"]      = ams_id;
-    j["print"]["slot_id"]     = slot_id;
+
+    // the new protocol
+    if (load_or_unload)
+    {
+        j["print"]["slot_id"] = slot_id;
+    }
+    else
+    {
+        j["print"]["slot_id"] = 255;// the new protocol to mark unload
+    }
+
     return this->publish_json(j.dump());
 }
 
diff --git a/src/slic3r/GUI/DeviceManager.hpp b/src/slic3r/GUI/DeviceManager.hpp
index 489ddb2a5..7ba543deb 100644
--- a/src/slic3r/GUI/DeviceManager.hpp
+++ b/src/slic3r/GUI/DeviceManager.hpp
@@ -1102,7 +1102,7 @@ public:
     // ams controls
     int command_ams_switch(int tray_index, int old_temp = 210, int new_temp = 210);
     int command_ams_change_filament(int tray_id, int old_temp = 210, int new_temp = 210);
-    int command_ams_change_filament2(int ams_id, int slot_id, int old_temp = 210, int new_temp = 210);
+    int command_ams_change_filament2(bool load_or_unload, int ams_id, int slot_id, int old_temp = 210, int new_temp = 210);
     int command_ams_user_settings(int ams_id, bool start_read_opt, bool tray_read_opt, bool remain_flag = false);
     int command_ams_switch_filament(bool switch_filament);
     int command_ams_air_print_detect(bool air_print_detect);
diff --git a/src/slic3r/GUI/StatusPanel.cpp b/src/slic3r/GUI/StatusPanel.cpp
index 8c33d3826..4f8c7c4e1 100644
--- a/src/slic3r/GUI/StatusPanel.cpp
+++ b/src/slic3r/GUI/StatusPanel.cpp
@@ -3932,18 +3932,26 @@ void StatusPanel::on_ams_load_curr()
 
         update_load_with_temp();
         //virtual tray
-        if (curr_ams_id.compare(std::to_string(VIRTUAL_TRAY_MAIN_ID)) == 0) {
+        if (curr_ams_id.compare(std::to_string(VIRTUAL_TRAY_MAIN_ID)) == 0 ||
+            curr_ams_id.compare(std::to_string(VIRTUAL_TRAY_DEPUTY_ID)) == 0)
+        {
+            int vt_slot_idx = 0;
+            if (curr_ams_id.compare(std::to_string(VIRTUAL_TRAY_DEPUTY_ID)) == 0)
+            {
+                vt_slot_idx = 1;
+            }
+
             int old_temp = -1;
             int new_temp = -1;
-            AmsTray* curr_tray = &obj->vt_slot[0];
+            AmsTray* curr_tray = &obj->vt_slot[vt_slot_idx];
 
             if (!curr_tray) return;
 
             try {
                 if (!curr_tray->nozzle_temp_max.empty() && !curr_tray->nozzle_temp_min.empty())
                     old_temp = (atoi(curr_tray->nozzle_temp_min.c_str()) + atoi(curr_tray->nozzle_temp_max.c_str())) / 2;
-                if (!obj->vt_slot[0].nozzle_temp_max.empty() && !obj->vt_slot[0].nozzle_temp_min.empty())
-                    new_temp = (atoi(obj->vt_slot[0].nozzle_temp_min.c_str()) + atoi(obj->vt_slot[0].nozzle_temp_max.c_str())) / 2;
+                if (!curr_tray->nozzle_temp_max.empty() && !curr_tray->nozzle_temp_min.empty())
+                    new_temp = (atoi(curr_tray->nozzle_temp_min.c_str()) + atoi(curr_tray->nozzle_temp_max.c_str())) / 2;
             }
             catch (...) {
                 ;
@@ -3952,7 +3960,7 @@ void StatusPanel::on_ams_load_curr()
             if (obj->is_enable_np) {
                 try {
                     if (!curr_ams_id.empty() && !curr_can_id.empty()) {
-                        obj->command_ams_change_filament2(stoi(curr_ams_id), 0, old_temp, new_temp);
+                        obj->command_ams_change_filament2(true, stoi(curr_ams_id), 0, old_temp, new_temp);
                     }
                 } catch (...) {}
             } else {
@@ -3992,7 +4000,7 @@ void StatusPanel::on_ams_load_curr()
         if (obj->is_enable_np) {
             try {
                 if (!curr_ams_id.empty() && !curr_can_id.empty()) {
-                    obj->command_ams_change_filament2(stoi(curr_ams_id), stoi(curr_can_id), old_temp, new_temp);
+                    obj->command_ams_change_filament2(true, stoi(curr_ams_id), stoi(curr_can_id), old_temp, new_temp);
                 }
             }
             catch (...){}
@@ -4055,7 +4063,7 @@ void StatusPanel::on_ams_unload(SimpleEvent &event)
                 std::string curr_can_id = m_ams_control->GetCurrentCan(curr_ams_id);
 
                 for (auto ext : obj->m_extder_data.extders) {
-                    if (ext.snow.ams_id == curr_ams_id && ext.snow.slot_id == curr_can_id) { obj->command_ams_change_filament2(stoi(curr_ams_id), 255); }
+                    if (ext.snow.ams_id == curr_ams_id && ext.snow.slot_id == curr_can_id) { obj->command_ams_change_filament2(false, stoi(curr_ams_id), 0); }
                 }
             } catch (...) {}
         } else {