diff --git a/gtk2_ardour/option_editor.cc b/gtk2_ardour/option_editor.cc
index 7b5a115794..c81423dab8 100644
--- a/gtk2_ardour/option_editor.cc
+++ b/gtk2_ardour/option_editor.cc
@@ -705,9 +705,7 @@ OptionEditor::mmc_receive_device_id_adjusted ()
 {
 	uint8_t id = (uint8_t) mmc_receive_device_id_spinner.get_value();
 
-	if (id != Config->get_mmc_receive_device_id()) {
-		Config->set_mmc_receive_device_id (id);
-	}
+	Config->set_mmc_receive_device_id (id);
 }
 
 void
@@ -715,9 +713,9 @@ OptionEditor::mmc_send_device_id_adjusted ()
 {
 	uint8_t id = (uint8_t) mmc_send_device_id_spinner.get_value();
 
-	if (id != Config->get_mmc_send_device_id()) {
-		Config->set_mmc_send_device_id (id);
-	}
+	cerr << "New send ID = " << (int) id << endl;
+
+	Config->set_mmc_send_device_id (id);
 }
 
 void
diff --git a/libs/ardour/session_midi.cc b/libs/ardour/session_midi.cc
index f6544b1cf6..b6396a6bca 100644
--- a/libs/ardour/session_midi.cc
+++ b/libs/ardour/session_midi.cc
@@ -138,6 +138,8 @@ Session::set_mmc_send_device_id (uint32_t device_id)
 {
 	if (mmc) {
 		mmc->set_send_device_id (device_id);
+		/* reset MMC buffer */
+		mmc_buffer[2] = mmc->send_device_id();
 	}
 }
 
@@ -176,8 +178,8 @@ Session::set_mmc_port (string port_tag)
 					MMC_ResponseSignature);
 
 	if (reset_id) {
-		mmc->set_receive_device_id (old_recv_device_id);
-		mmc->set_send_device_id (old_send_device_id);
+		set_mmc_receive_device_id (old_recv_device_id);
+		set_mmc_send_device_id (old_send_device_id);
 	}
 
 	mmc->Play.connect 
diff --git a/libs/ardour/session_state.cc b/libs/ardour/session_state.cc
index 1f8a4e1fbe..e39ebf72f2 100644
--- a/libs/ardour/session_state.cc
+++ b/libs/ardour/session_state.cc
@@ -3169,15 +3169,11 @@ Session::config_changed (const char* parameter_name)
 
 	} else if (PARAM_IS ("mmc-device-id") || PARAM_IS ("mmc-receive-device-id")) {
 
-		if (mmc) {
-			mmc->set_receive_device_id (Config->get_mmc_receive_device_id());
-		}
+		set_mmc_receive_device_id (Config->get_mmc_receive_device_id());
 
 	} else if (PARAM_IS ("mmc-send-device-id")) {
 
-		if (mmc) {
-			mmc->set_send_device_id (Config->get_mmc_send_device_id());
-		}
+		set_mmc_send_device_id (Config->get_mmc_send_device_id());
 
 	} else if (PARAM_IS ("midi-control")) {