diff --git a/libs/surfaces/mackie/controls.h b/libs/surfaces/mackie/controls.h
index 75c85ec246..e2157b49ff 100644
--- a/libs/surfaces/mackie/controls.h
+++ b/libs/surfaces/mackie/controls.h
@@ -163,7 +163,7 @@ public:
 		type_pot = 0xb0 
 	};
 	
-	Control (int id, int ordinal, std::string name, Group & group);
+	Control (int id, int ordinal, std::string name, Group& group);
 	virtual ~Control() {}
 	
 	virtual const Led & led() const { throw MackieControlException ("no led available"); }
@@ -212,7 +212,7 @@ private:
 	int _id;
 	int _ordinal;
 	std::string _name;
-	Group & _group;
+	Group& _group;
 	bool _in_use;
 };
 
diff --git a/libs/surfaces/mackie/mackie_port.cc b/libs/surfaces/mackie/mackie_port.cc
index 2dd36ffd9b..ae9a7bf1fb 100644
--- a/libs/surfaces/mackie/mackie_port.cc
+++ b/libs/surfaces/mackie/mackie_port.cc
@@ -140,17 +140,18 @@ MidiByteArray calculate_challenge_response (MidiByteArray::iterator begin, MidiB
 // not used right now
 MidiByteArray MackiePort::host_connection_query (MidiByteArray & bytes)
 {
+	MidiByteArray response;
+
 	// handle host connection query
 	DEBUG_TRACE (DEBUG::MackieControl, string_compose ("host connection query: %1\n", bytes));
 	
 	if  (bytes.size() != 18) {
 		finalise_init (false);
 		cerr << "expecting 18 bytes, read " << bytes << " from " << input_port().name() << endl;
-		return;
+		return response;
 	}
 
 	// build and send host connection reply
-	MidiByteArray response;
 	response << 0x02;
 	copy (bytes.begin() + 6, bytes.begin() + 6 + 7, back_inserter (response));
 	response << calculate_challenge_response (bytes.begin() + 6 + 7, bytes.begin() + 6 + 7 + 4);