show mac address

src/main.cpp

@@ -732,6 +732,9 @@ void setup()
   adcAttachPin(_VBAT);
   adcStart(_VBAT);
 
+  Serial.print("MAC Address: ");
+  Serial.println(ota.getMAC());
+
   #define BME_SDA 21
   #define BME_SCL 22
   Wire.begin(BME_SDA, BME_SCL);