diff --git a/DCCTimerSTM32.cpp b/DCCTimerSTM32.cpp
index 0917455a..df00df38 100644
--- a/DCCTimerSTM32.cpp
+++ b/DCCTimerSTM32.cpp
@@ -70,9 +70,9 @@ HardwareSerial Serial5(PD2, PC12);  // Rx=PD2, Tx=PC12 -- UART5 - F446RE
       defined(ARDUINO_NUCLEO_F429ZI) || defined(ARDUINO_NUCLEO_F439ZI) || defined(ARDUINO_NUCLEO_F4X9ZI)
 // Nucleo-144 boards don't have Serial1 defined by default
 HardwareSerial Serial6(PG9, PG14);  // Rx=PG9, Tx=PG14 -- USART6
-HardwareSerial Serial5(PD2, PC12);  // Rx=PD2, Tx=PC12 -- UART5
-#if !defined(ARDUINO_NUCLEO_F412ZG)
-  HardwareSerial Serial2(PD6, PD5);  // Rx=PD6, Tx=PD5 -- UART5
+HardwareSerial Serial2(PD6, PD5);  // Rx=PD6, Tx=PD5 -- UART2
+#if !defined(ARDUINO_NUCLEO_F412ZG)  // F412ZG does not have UART5
+  HardwareSerial Serial5(PD2, PC12);  // Rx=PD2, Tx=PC12 -- UART5
 #endif  
 // Serial3 is defined to use USART3 by default, but is in fact used as the diag console
 // via the debugger on the Nucleo-144. It is therefore unavailable for other DCC-EX uses like WiFi, DFPlayer, etc.
@@ -328,7 +328,7 @@ void DCCTimer::DCCEXanalogWriteFrequencyInternal(uint8_t pin, uint32_t frequency
     if (pin_timer[pin] != NULL)
     {
       pin_timer[pin]->setPWM(pin_channel[pin], pin, frequency, 0); // set frequency in Hertz, 0% dutycycle
-      DIAG(F("DCCEXanalogWriteFrequency::Pin %d on Timer %d, frequency %d"), pin, pin_channel[pin], frequency);
+      DIAG(F("DCCEXanalogWriteFrequency::Pin %d on Timer Channel %d, frequency %d"), pin, pin_channel[pin], frequency);
     }
     else
       DIAG(F("DCCEXanalogWriteFrequency::failed to allocate HardwareTimer instance!"));
diff --git a/I2CManager_STM32.h b/I2CManager_STM32.h
index 109c89b4..45c924fb 100644
--- a/I2CManager_STM32.h
+++ b/I2CManager_STM32.h
@@ -1,5 +1,5 @@
 /*
- *  © 2022-23 Paul M Antoine
+ *  © 2022-24 Paul M Antoine
  *  © 2023, Neil McKechnie
  *  All rights reserved.
  *
@@ -185,7 +185,7 @@ void I2CManagerClass::I2C_init()
   GPIOB->OTYPER |= (1<<8) | (1<<9);           // PB8 and PB9 set to open drain output capability
   GPIOB->OSPEEDR |= (3<<(8*2)) | (3<<(9*2));  // PB8 and PB9 set to High Speed mode
   GPIOB->PUPDR &= ~((3<<(8*2)) | (3<<(9*2))); // Clear all PUPDR bits for PB8 and PB9
-  GPIOB->PUPDR |= (1<<(8*2)) | (1<<(9*2));    // PB8 and PB9 set to pull-up capability
+  // GPIOB->PUPDR |= (1<<(8*2)) | (1<<(9*2));    // PB8 and PB9 set to pull-up capability
   // Alt Function High register routing pins PB8 and PB9 for I2C1:
   // Bits (3:2:1:0) = 0:1:0:0 --> AF4 for pin PB8
   // Bits (7:6:5:4) = 0:1:0:0 --> AF4 for pin PB9
diff --git a/TrackManager.cpp b/TrackManager.cpp
index a1641422..c6a30add 100644
--- a/TrackManager.cpp
+++ b/TrackManager.cpp
@@ -151,8 +151,8 @@ void TrackManager::setDCCSignal( bool on) {
   HAVE_PORTD(shadowPORTD=PORTD);
   HAVE_PORTE(shadowPORTE=PORTE);
   HAVE_PORTF(shadowPORTF=PORTF);
-  HAVE_PORTG(shadowPORTF=PORTG);
-  HAVE_PORTH(shadowPORTF=PORTH);
+  HAVE_PORTG(shadowPORTG=PORTG);
+  HAVE_PORTH(shadowPORTH=PORTH);
   APPLY_BY_MODE(TRACK_MODE_MAIN,setSignal(on));
   HAVE_PORTA(PORTA=shadowPORTA);
   HAVE_PORTB(PORTB=shadowPORTB);
@@ -160,8 +160,8 @@ void TrackManager::setDCCSignal( bool on) {
   HAVE_PORTD(PORTD=shadowPORTD);
   HAVE_PORTE(PORTE=shadowPORTE);
   HAVE_PORTF(PORTF=shadowPORTF);
-  HAVE_PORTG(shadowPORTF=PORTG);
-  HAVE_PORTH(shadowPORTF=PORTH);
+  HAVE_PORTG(shadowPORTG=PORTG);
+  HAVE_PORTH(shadowPORTH=PORTH);
 }
 
 // setPROGSignal(), called from interrupt context
@@ -173,8 +173,8 @@ void TrackManager::setPROGSignal( bool on) {
   HAVE_PORTD(shadowPORTD=PORTD);
   HAVE_PORTE(shadowPORTE=PORTE);
   HAVE_PORTF(shadowPORTF=PORTF);
-  HAVE_PORTG(shadowPORTF=PORTG);
-  HAVE_PORTH(shadowPORTF=PORTH);
+  HAVE_PORTG(shadowPORTG=PORTG);
+  HAVE_PORTH(shadowPORTH=PORTH);
   APPLY_BY_MODE(TRACK_MODE_PROG,setSignal(on));
   HAVE_PORTA(PORTA=shadowPORTA);
   HAVE_PORTB(PORTB=shadowPORTB);
@@ -182,8 +182,8 @@ void TrackManager::setPROGSignal( bool on) {
   HAVE_PORTD(PORTD=shadowPORTD);
   HAVE_PORTE(PORTE=shadowPORTE);
   HAVE_PORTF(PORTF=shadowPORTF);
-  HAVE_PORTG(shadowPORTF=PORTG);
-  HAVE_PORTH(shadowPORTF=PORTH);
+  HAVE_PORTG(shadowPORTG=PORTG);
+  HAVE_PORTH(shadowPORTH=PORTH);
 }
 
 // setDCSignal(), called from normal context
diff --git a/WifiInterface.cpp b/WifiInterface.cpp
index fcf99324..6b6ec4af 100644
--- a/WifiInterface.cpp
+++ b/WifiInterface.cpp
@@ -72,8 +72,9 @@ Stream * WifiInterface::wifiStream;
 #elif defined(ARDUINO_NUCLEO_F413ZH) || defined(ARDUINO_NUCLEO_F429ZI) \
     || defined(ARDUINO_NUCLEO_F446ZE) || defined(ARDUINO_NUCLEO_F412ZG) \
     || defined(ARDUINO_NUCLEO_F439ZI) || defined(ARDUINO_NUCLEO_F4X9ZI)
-#define NUM_SERIAL 2
+#define NUM_SERIAL 3
 #define SERIAL1 Serial6
+#define SERIAL3 Serial2
 #else
 #warning This variant of Nucleo not yet explicitly supported
 #endif
diff --git a/version.h b/version.h
index c6d0556a..a955a868 100644
--- a/version.h
+++ b/version.h
@@ -3,7 +3,8 @@
 
 #include "StringFormatter.h"
 
-#define VERSION "5.2.82"
+#define VERSION "5.2.83"
+// 5.2.83 - Various STM32 related fixes for serial ports, I2C pullups now turned off, and shadowing of PORTG/PORTH for TrackManager now correct
 // 5.2.82 - TrackManager and EXRAIL: Introduce more consistent names for <= ...> and SET_TRACK
 // 5.2.81 - STM32 Ethernet boards support, also now have specific EX8874 motor driver definition
 // 5.2.80 - EthernetInterface upgrade, including STM32 Ethernet support