diff --git a/src/concurrency/OSThread.cpp b/src/concurrency/OSThread.cpp
index 4a46c7b0e..c52efd626 100644
--- a/src/concurrency/OSThread.cpp
+++ b/src/concurrency/OSThread.cpp
@@ -1,9 +1,9 @@
 #include "OSThread.h"
 #include "configuration.h"
-#ifdef DEBUG_HEAP
+#ifdef HAS_SCREEN
 #include "graphics/Screen.h"
-#include "main.h"
 #endif
+#include "main.h"
 #include <assert.h>
 
 namespace concurrency
@@ -83,18 +83,21 @@ void OSThread::run()
 #endif
     currentThread = this;
     auto newDelay = runOnce();
-#ifdef DEBUG_HEAP
+#ifdef ARCH_ESP32
     auto newHeap = ESP.getFreeHeap();
+    if (newHeap < 10000) {
+        LOG_DEBUG("\n\n====== heap too low [10000] -> reboot in 5s ======\n\n");
+#ifdef HAS_SCREEN
+        screen->startRebootScreen();
+#endif
+        rebootAtMsec = millis() + 5000;
+    }
+#ifdef DEBUG_HEAP
     if (newHeap < heap)
         LOG_DEBUG("------ Thread %s leaked heap %d -> %d (%d) ------\n", ThreadName.c_str(), heap, newHeap, newHeap - heap);
     if (heap < newHeap)
         LOG_DEBUG("++++++ Thread %s freed heap %d -> %d (%d) ++++++\n", ThreadName.c_str(), heap, newHeap, newHeap - heap);
-
-    if (newHeap < 10000) {
-        LOG_DEBUG("\n\n====== heap too low [10000] -> reboot in 5s ======\n\n");
-        screen->startRebootScreen();
-        rebootAtMsec = millis() + 5000;
-    }
+#endif
 #endif
 
     runned();
diff --git a/src/modules/SerialModule.cpp b/src/modules/SerialModule.cpp
index d740ba607..5637f7eb1 100644
--- a/src/modules/SerialModule.cpp
+++ b/src/modules/SerialModule.cpp
@@ -12,7 +12,7 @@
         A simple interface to send messages over the mesh network by sending strings
         over a serial port.
 
-        Default is to use RX GPIO 16 and TX GPIO 17.
+        There are no PIN defaults, you have to enable the second serial port yourself.
 
     Need help with this module? Post your question on the Meshtastic Discourse:
        https://meshtastic.discourse.group
@@ -46,8 +46,6 @@
 
 #if (defined(ARCH_ESP32) || defined(ARCH_NRF52)) && !defined(TTGO_T_ECHO) && !defined(CONFIG_IDF_TARGET_ESP32S2)
 
-#define RXD2 16
-#define TXD2 17
 #define RX_BUFFER 128
 #define TIMEOUT 250
 #define BAUD 38400
@@ -102,7 +100,7 @@ int32_t SerialModule::runOnce()
     // moduleConfig.serial.timeout = 1000;
     // moduleConfig.serial.echo = 1;
 
-    if (moduleConfig.serial.enabled) {
+    if (moduleConfig.serial.enabled && moduleConfig.serial.rxd && moduleConfig.serial.txd) {
 
         if (firstTime) {
 
@@ -165,9 +163,6 @@ int32_t SerialModule::runOnce()
 
             if (moduleConfig.serial.rxd && moduleConfig.serial.txd) {
                 Serial2.begin(baud, SERIAL_8N1, moduleConfig.serial.rxd, moduleConfig.serial.txd);
-
-            } else {
-                Serial2.begin(baud, SERIAL_8N1, RXD2, TXD2);
             }
 #else
             if (moduleConfig.serial.rxd && moduleConfig.serial.txd)
diff --git a/src/mqtt/MQTT.cpp b/src/mqtt/MQTT.cpp
index 42dad45bb..5e32050ad 100644
--- a/src/mqtt/MQTT.cpp
+++ b/src/mqtt/MQTT.cpp
@@ -53,10 +53,8 @@ void MQTT::onPublish(char *topic, byte *payload, unsigned int length)
             for (int i = 0; i < 3; i++) {
                 ptr = strtok(NULL, "/");
             }
-            LOG_DEBUG("Looking for Channel name: %s\n", ptr);
             meshtastic_Channel sendChannel = channels.getByName(ptr);
-            LOG_DEBUG("Found Channel name: %s (Index %d)\n", channels.getGlobalId(sendChannel.settings.channel_num),
-                      sendChannel.settings.channel_num);
+            LOG_DEBUG("Found Channel name: %s (Index %d)\n", channels.getGlobalId(sendChannel.index), sendChannel.index);
 
             if ((json.find("sender") != json.end()) && (json.find("payload") != json.end()) &&
                 (json.find("type") != json.end()) && json["type"]->IsString() &&
@@ -70,7 +68,7 @@ void MQTT::onPublish(char *topic, byte *payload, unsigned int length)
                     // construct protobuf data packet using TEXT_MESSAGE, send it to the mesh
                     meshtastic_MeshPacket *p = router->allocForSending();
                     p->decoded.portnum = meshtastic_PortNum_TEXT_MESSAGE_APP;
-                    p->channel = sendChannel.settings.channel_num;
+                    p->channel = sendChannel.index;
                     if (sendChannel.settings.downlink_enabled) {
                         if (jsonPayloadStr.length() <= sizeof(p->decoded.payload.bytes)) {
                             memcpy(p->decoded.payload.bytes, jsonPayloadStr.c_str(), jsonPayloadStr.length());
@@ -104,7 +102,7 @@ void MQTT::onPublish(char *topic, byte *payload, unsigned int length)
                     // construct protobuf data packet using POSITION, send it to the mesh
                     meshtastic_MeshPacket *p = router->allocForSending();
                     p->decoded.portnum = meshtastic_PortNum_POSITION_APP;
-                    p->channel = sendChannel.settings.channel_num;
+                    p->channel = sendChannel.index;
                     if (sendChannel.settings.downlink_enabled) {
                         p->decoded.payload.size =
                             pb_encode_to_bytes(p->decoded.payload.bytes, sizeof(p->decoded.payload.bytes),