--- a/Discovery/Src/tMenuEditHardware.c	Mon Nov 01 12:39:34 2021 +0100
+++ b/Discovery/Src/tMenuEditHardware.c	Fri Aug 19 11:30:24 2022 +0200
@@ -336,11 +336,18 @@
 		switch(settingsGetPointer()->ppo2sensors_source)
 		{
 			default:
-			case O2_SENSOR_SOURCE_OPTIC: text[1] = TXT2BYTE_O2IFOptic;
+			case O2_SENSOR_SOURCE_OPTIC: 	text[1] = TXT2BYTE_O2IFOptic;
+											text[2] = 0;
+				break;
+			case O2_SENSOR_SOURCE_ANALOG: 	text[1] = TXT2BYTE_O2IFAnalog;
+											text[2] = 0;
 				break;
-			case O2_SENSOR_SOURCE_ANALOG: text[1] = TXT2BYTE_O2IFAnalog;
+#ifdef ENABLE_SENTINEL_MODE
+			case O2_SENSOR_SOURCE_SENTINEL: snprintf(text, 10,"Sentinel");
+				break;
+#endif
 		}
-		text[2] = 0;
+
 		write_label_var(  400, 800, ME_Y_LINE6, &FontT48, text);
     }
     tMenuEdit_refresh_field(StMHARD3_O2_Sensor1);
@@ -378,12 +385,16 @@
     write_field_on_off(StMHARD3_O2_Sensor2,	 30, 95, ME_Y_LINE2,  &FontT48, "", sensorActive[1]);
     write_field_on_off(StMHARD3_O2_Sensor3,	 30, 95, ME_Y_LINE3,  &FontT48, "", sensorActive[2]);
 
-    if(settingsGetPointer()->ppo2sensors_source == O2_SENSOR_SOURCE_ANALOG)
+    if((settingsGetPointer()->ppo2sensors_source == O2_SENSOR_SOURCE_ANALOG)
+#ifdef ENABLE_SENTINEL_MODE
+    		|| (settingsGetPointer()->ppo2sensors_source == O2_SENSOR_SOURCE_SENTINEL)
+#endif
+	)
     {
         write_label_fix(   30, 800, ME_Y_LINE4, &FontT48, TXT2BYTE_O2Calib);
         write_label_var(  400, 800, ME_Y_LINE4, &FontT48, "\016\016 %\017");
 
-        write_field_toggle(StMHARD3_O2_Calibrate,	400, 800, ME_Y_LINE4, &FontT48, "", 21, 100);
+        write_field_toggle(StMHARD3_O2_Calibrate,	400, 800, ME_Y_LINE4, &FontT48, "", 21, 98);
     }
 
     text[0] = TXT_Fallback;
@@ -399,7 +410,11 @@
     setEvent(StMHARD3_O2_Sensor1, (uint32_t)OnAction_Sensor1);
     setEvent(StMHARD3_O2_Sensor2, (uint32_t)OnAction_Sensor2);
     setEvent(StMHARD3_O2_Sensor3, (uint32_t)OnAction_Sensor3);
-    if(settingsGetPointer()->ppo2sensors_source == O2_SENSOR_SOURCE_ANALOG)
+    if((settingsGetPointer()->ppo2sensors_source == O2_SENSOR_SOURCE_ANALOG)
+#ifdef ENABLE_SENTINEL_MODE
+    		|| (settingsGetPointer()->ppo2sensors_source == O2_SENSOR_SOURCE_SENTINEL)
+#endif
+	)
     {
     	setEvent(StMHARD3_O2_Calibrate, (uint32_t)OnAction_O2_Calibrate);
     }
@@ -517,7 +532,7 @@
     {
 		if(O2_calib_gas == 21)
 		{
-			O2_calib_gas = 100;
+			O2_calib_gas = 98;
 		}
 		else
 		{
@@ -537,11 +552,8 @@
 {
     uint8_t source = settingsGetPointer()->ppo2sensors_source;
 
-    if(source == O2_SENSOR_SOURCE_OPTIC)
-    {
-    	source = O2_SENSOR_SOURCE_ANALOG;
-    }
-    else
+    source++;
+    if(source == O2_SENSOR_SOURCE_MAX)
     {
     	source = O2_SENSOR_SOURCE_OPTIC;
     }