diff --git a/src/connect/marlin_printer.cpp b/src/connect/marlin_printer.cpp
index 8a90f0fbd4..b4da419dc7 100644
--- a/src/connect/marlin_printer.cpp
+++ b/src/connect/marlin_printer.cpp
@@ -220,7 +220,7 @@ Printer::Params MarlinPrinter::params() const {
     params.time_to_pause = marlin_vars()->time_to_pause;
     params.progress_percent = marlin_vars()->sd_percent_done;
     params.filament_used = Odometer_s::instance().get_extruded_all();
-    params.nozzle_diameter = config_store().get_nozzle_diameter(params.preferred_slot());
+    params.nozzle_diameter = config_store().get_nozzle_diameter(params.preferred_head());
     params.has_usb = marlin_vars()->media_inserted;
     params.can_start_download = can_start_download;
 
diff --git a/src/connect/printer.cpp b/src/connect/printer.cpp
index 3a54495c07..d8de14f3bc 100644
--- a/src/connect/printer.cpp
+++ b/src/connect/printer.cpp
@@ -187,4 +187,12 @@ uint8_t Printer::Params::preferred_slot() const {
     }
 }
 
+uint8_t Printer::Params::preferred_head() const {
+#if HAS_TOOLCHANGER()
+    return preferred_slot();
+#else
+    return 0;
+#endif
+}
+
 } // namespace connect_client
diff --git a/src/connect/printer.hpp b/src/connect/printer.hpp
index 437d913d1a..a10c56ae17 100644
--- a/src/connect/printer.hpp
+++ b/src/connect/printer.hpp
@@ -145,6 +145,13 @@ class Printer {
         }
         // Either the active slot, if any, or the first available slot if no slot is active.
         uint8_t preferred_slot() const;
+        // Either the active head, if any, or the first available one.
+        //
+        // This is the same as preferred_slot for XL (where tools and slots are
+        // the same thing), but always returns 0 on other printers, including
+        // ones with MMU (they have multiple filament slots, but just one head
+        // / nozzle / ...).
+        uint8_t preferred_head() const;
     };
 
     struct Config {
diff --git a/src/connect/render.cpp b/src/connect/render.cpp
index 32306f0bef..28738d8db2 100644
--- a/src/connect/render.cpp
+++ b/src/connect/render.cpp
@@ -123,7 +123,7 @@ namespace {
             // need to coordinate with Connect, as these are probably
             // "essential" fields right now.
             if (telemetry.mode == SendTelemetry::Mode::Full) {
-                JSON_FIELD_FFIXED("temp_nozzle", params.slots[params.preferred_slot()].temp_nozzle, 1) JSON_COMMA;
+                JSON_FIELD_FFIXED("temp_nozzle", params.slots[params.preferred_head()].temp_nozzle, 1) JSON_COMMA;
                 JSON_FIELD_FFIXED("temp_bed", params.temp_bed, 1) JSON_COMMA;
                 JSON_FIELD_FFIXED("target_nozzle", params.target_nozzle, 1) JSON_COMMA;
                 JSON_FIELD_FFIXED("target_bed", params.target_bed, 1) JSON_COMMA;
@@ -148,8 +148,8 @@ namespace {
                 }
                 JSON_FIELD_FFIXED("axis_z", params.pos[Printer::Z_AXIS_POS], 2) JSON_COMMA;
                 if (params.has_job) {
-                    JSON_FIELD_INT("fan_extruder", params.slots[params.preferred_slot()].heatbreak_fan_rpm) JSON_COMMA;
-                    JSON_FIELD_INT("fan_print", params.slots[params.preferred_slot()].print_fan_rpm) JSON_COMMA;
+                    JSON_FIELD_INT("fan_extruder", params.slots[params.preferred_head()].heatbreak_fan_rpm) JSON_COMMA;
+                    JSON_FIELD_INT("fan_print", params.slots[params.preferred_head()].print_fan_rpm) JSON_COMMA;
                     JSON_FIELD_FFIXED("filament", params.filament_used, 1) JSON_COMMA;
                 }