diff --git a/src/slic3r/GUI/DeviceCore/DevFilaSystem.cpp b/src/slic3r/GUI/DeviceCore/DevFilaSystem.cpp
index 0cd6fb2c2e..d4a7f20241 100644
--- a/src/slic3r/GUI/DeviceCore/DevFilaSystem.cpp
+++ b/src/slic3r/GUI/DeviceCore/DevFilaSystem.cpp
@@ -221,15 +221,18 @@ wxString DevAms::GetDisplayName() const
 
 int DevAms::GetSlotCount() const
 {
-    // GetAmsType() maps AMS_LITE_MIXED -> AMS_LITE, so N9 reports 4 slots like AMS-Lite.
-    auto ams_type = GetAmsType();
-    if (ams_type == AMS || ams_type == AMS_LITE || ams_type == N3F)
-    {
-        return 4;
-    }
-    else if (ams_type == N3S)
-    {
-        return 1;
+    if (wxTheApp != nullptr && GUI::wxGetApp().preset_bundle != nullptr &&
+        GUI::wxGetApp().preset_bundle->is_bbl_vendor()) {
+        // GetAmsType() maps AMS_LITE_MIXED -> AMS_LITE, so N9 reports 4 slots like AMS-Lite.
+        auto ams_type = GetAmsType();
+        if (ams_type == AMS || ams_type == AMS_LITE || ams_type == N3F)
+        {
+            return 4;
+        }
+        else if (ams_type == N3S)
+        {
+            return 1;
+        }
     }
 
     return static_cast<int>(m_trays.size());
diff --git a/src/slic3r/GUI/DeviceCore/DevNozzleSystem.cpp b/src/slic3r/GUI/DeviceCore/DevNozzleSystem.cpp
index 304d84097f..d4f50ed10b 100644
--- a/src/slic3r/GUI/DeviceCore/DevNozzleSystem.cpp
+++ b/src/slic3r/GUI/DeviceCore/DevNozzleSystem.cpp
@@ -176,7 +176,9 @@ int DevNozzle::GetLogicExtruderId() const
 {
     int total_ext_count = GetTotalExtruderCount();
 
-    if (GUI::wxGetApp().preset_bundle->is_bbl_vendor()) {
+    const bool is_bbl_vendor = wxTheApp != nullptr && GUI::wxGetApp().preset_bundle != nullptr &&
+                               GUI::wxGetApp().preset_bundle->is_bbl_vendor();
+    if (is_bbl_vendor) {
         if (total_ext_count == 1) {
             return LOGIC_UNIQUE_EXTRUDER_ID;
         } else if (total_ext_count == 2) {
@@ -201,7 +203,9 @@ int DevNozzle::GetLogicExtruderId() const
 
 int DevNozzle::GetExtruderId() const
 {
-    if (GUI::wxGetApp().preset_bundle->is_bbl_vendor()) {
+    const bool is_bbl_vendor = wxTheApp != nullptr && GUI::wxGetApp().preset_bundle != nullptr &&
+                               GUI::wxGetApp().preset_bundle->is_bbl_vendor();
+    if (is_bbl_vendor) {
         int total_ext_count = GetTotalExtruderCount();
         if (total_ext_count == 1) {
             return MAIN_EXTRUDER_ID;
diff --git a/src/slic3r/GUI/Widgets/MultiNozzleSync.cpp b/src/slic3r/GUI/Widgets/MultiNozzleSync.cpp
index b26bcf80f4..6f7fc4a4af 100644
--- a/src/slic3r/GUI/Widgets/MultiNozzleSync.cpp
+++ b/src/slic3r/GUI/Widgets/MultiNozzleSync.cpp
@@ -419,6 +419,14 @@ ExtruderBadge::ExtruderBadge(wxWindow* parent) : wxPanel(parent)
 
 void ExtruderBadge::SetExtruderInfo(int extruder_id, const std::string& diameter, const NozzleVolumeType& volume_type)
 {
+    // The badge renders exactly two extruders (left/right). A generic non-BBL printer with
+    // N > 2 can report an out-of-range id here (see MultiNozzleStatusTable::UpdateRackInfo);
+    // reject it rather than writing past the two-element lists.
+    if (extruder_id < 0 || extruder_id >= static_cast<int>(m_diameter_list.size())) {
+        BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << ": out-of-range extruder_id " << extruder_id;
+        return;
+    }
+
     m_diameter_list[extruder_id] = diameter;
     m_volume_type_list[extruder_id] = volume_type;