MQTT message loop fixed

build-flags/build_flags_lighthub21

@@ -10,6 +10,7 @@
 -DARDUINO_OTA_MDNS_DISABLE
 -DMDNS_ENABLE
 -DTIMER_INT
+#-DFLASH_OFFSET=-256
 
 # Serial parameters for LEGACY Modbus
 -DMODBUS_DIMMER_PARAM=SERIAL_8E1

lighthub/main.cpp

@@ -369,7 +369,7 @@ int intopic;
 
 void mqttCallback(char *topic, byte *payload, unsigned int length) 
 {
-    if (!payload) return;
+    if (!payload || !payload[0]) return;
     payload[length] = 0;
 
     int fr = freeRam();