Restore the extruder name fallback and fix the loading-busy check

src/slic3r/GUI/DeviceCore/DevConfigUtil.cpp

@@ -374,15 +374,19 @@ std::string DevPrinterConfigUtil::get_toolhead_display_name(
         }
     }
 
-    // Fallback: all dual-extruder printers should have tool_head_display_names configured.
+    // Orca: models that ship no tool_head_display_names (e.g. H2D/H2S) must still get distinct
-    // This is a safety net only — return a generic name.
+    // per-extruder labels, so fall back to the previous programmatic Left/Right construction.
+    // Engages only when the config lookup above yields nothing, so models that ship the key
+    // behave exactly like the reference.
     if (result.empty()) {
-        static const std::map<ToolHeadComponent, std::string> fallback_names = {
+        const std::string side = ext_id == DEPUTY_EXTRUDER_ID ? "Left" : "Right";
-            { ToolHeadComponent::Extruder, "Extruder" },
+        const std::string component_name = component == ToolHeadComponent::Extruder ? "Extruder" :
-            { ToolHeadComponent::Nozzle,   "Nozzle" },
+                                           component == ToolHeadComponent::Hotend ? "Hotend" : "Nozzle";
-            { ToolHeadComponent::Hotend,   "Hotend" }
+        result = side + " " + component_name;
-        };
+        if (name_case == ToolHeadNameCase::SentenceCase && result.size() > side.size() + 1)
-        result = fallback_names.at(component);
+            result[side.size() + 1] = static_cast<char>(std::tolower(static_cast<unsigned char>(result[side.size() + 1])));
+        else if (name_case == ToolHeadNameCase::LowerCase)
+            std::transform(result.begin(), result.end(), result.begin(), [](unsigned char c) { return static_cast<char>(std::tolower(c)); });
     }
 
     // short_name: return only the role prefix (e.g. "Main" from "Main Nozzle")

src/slic3r/GUI/DeviceCore/DevExtruderSystem.cpp

@@ -271,7 +271,7 @@ namespace Slic3r
         system->m_current_loading_extder_id = INVALID_EXTRUDER_ID;
         if (!system->m_extders[MAIN_EXTRUDER_ID].m_star.ams_id.empty())
         {
-            system->m_current_busy_for_loading = (system->m_extders[MAIN_EXTRUDER_ID].m_snow == system->m_extders[MAIN_EXTRUDER_ID].m_star);
+            system->m_current_busy_for_loading = (system->m_extders[MAIN_EXTRUDER_ID].m_snow != system->m_extders[MAIN_EXTRUDER_ID].m_star);
             if (system->m_current_busy_for_loading)
             {
                 system->m_current_loading_extder_id = MAIN_EXTRUDER_ID;

src/slic3r/GUI/DeviceCore/DevExtruderSystem.h

@@ -22,6 +22,7 @@ struct DevAmsSlotInfo
     std::string slot_id;
 
 public:
+    bool operator!=(const DevAmsSlotInfo& other) const { return !(*this == other); }
     bool operator==(const DevAmsSlotInfo& other) const { return ams_id == other.ams_id && slot_id == other.slot_id;}
 };