diff --git a/firmware/Include/main.h b/firmware/Include/main.h
index 60655c8..6bdfffb 100644
--- a/firmware/Include/main.h
+++ b/firmware/Include/main.h
@@ -55,6 +55,7 @@ void Error_Handler(void);
 
 void set_input(uint8_t channel);
 void set_attenuation(uint8_t left, uint8_t right);
+void set_mute(uint8_t mute);
 
 /* USER CODE BEGIN EFP */
 
diff --git a/firmware/Src/main.c b/firmware/Src/main.c
index 2f137f3..d56aab1 100644
--- a/firmware/Src/main.c
+++ b/firmware/Src/main.c
@@ -102,23 +102,55 @@ int test_button_pressed() {
 #undef TEST_BUTTON
 }
 
+struct ui_state {
+  uint8_t oldchannel;
+  uint8_t mute;
+} ui_state = {
+  .oldchannel = -1,
+  .mute = 0,
+};
 
 void set_input(uint8_t channel) {
-	static uint8_t oldchannel = -1;
-	if (channel == oldchannel || channel >= 6)
+	if (ui_state.oldchannel == channel || channel >= 6)
 		return;
 
-  channel = channel;
-	set_input_led(oldchannel, 0);
-	set_input_led(channel, 1);
-  
-  // invert bd inputs to match the numbers on the case
-	bd_set_input(&hi2c1, 5-channel);
-	oldchannel = channel;
+	set_input_led(ui_state.oldchannel, 0);
+
+  // do not disturb the mute mode
+  if (!ui_state.mute)
+  {
+	  set_input_led(channel, 1);
+
+	  // invert bd inputs to match the numbers on the case
+    bd_set_input(&hi2c1, 5-channel);
+  }
+
+	ui_state.oldchannel = channel;
 
 	printf("C%d\n", channel);
 }
 
+void set_mute(uint8_t mute) {
+  if(ui_state.mute == mute)
+    return;
+
+  if (0 == (ui_state.mute = mute)) {
+    // hack to make reactivation of the last channel easier
+    uint8_t old_input = ui_state.oldchannel;
+    ui_state.oldchannel = -1;
+
+    set_input(old_input);
+    HAL_GPIO_WritePin(USER_LED_GPIO_Port, USER_LED_Pin, 0);
+  }
+  else {
+    HAL_GPIO_WritePin(USER_LED_GPIO_Port, USER_LED_Pin, 1);
+    set_input_led(ui_state.oldchannel, 0);
+    bd_set_input(&hi2c1, BD_INPUT_MUTE);
+  }
+
+  printf("M%d\n", ui_state.mute?1:0);
+}
+
 void set_attenuation(uint8_t left, uint8_t right) {
 	bd_set_attenuation(&hi2c1, 0, left);
 	bd_set_attenuation(&hi2c1, 1, right);
@@ -168,6 +200,8 @@ int main(void)
   // reset set input
   set_input(input);
   set_attenuation(0,0);
+  int count = 0;
+  int button_timeout = 0;
   /* USER CODE END 2 */
 
   /* Infinite loop */
@@ -180,9 +214,26 @@ int main(void)
 
 	  // handle button inputs
 	  input = test_button_pressed();
-	  if (0 <= input) {
+	  if (6 > input) {
 		  set_input(input);
-	  }
+      
+      if (100 < ++count) {
+        count = 0;
+        button_timeout++;
+      }
+
+      //printf("%d\n", count);
+
+      if (1000 < button_timeout) {
+        // long press, toggle mute
+        set_mute(!ui_state.mute);
+        button_timeout = 0;
+      }
+
+	  } else {
+      count = 0;
+      button_timeout = 0;
+    }
 
 	  // parse serial commands
 	  parse_buffer();
diff --git a/firmware/Src/message_parser.c b/firmware/Src/message_parser.c
index ee23b1a..695565d 100644
--- a/firmware/Src/message_parser.c
+++ b/firmware/Src/message_parser.c
@@ -150,6 +150,14 @@ int parse_buffer() {
 		printf("%c%d\n", temp, bd_set_attenuation(&hi2c1, temp == 'R', att&0xFF));
 	}
 		break;
+	case 'M':
+	{
+		uint16_t mute;
+		if (next_arg_unsigned(&mute)) break;
+		
+		set_mute(mute);
+	}
+		break;
 	case 'B':
 	case 'T':