diff --git a/radio/src/targets/sky9x/board.h b/radio/src/targets/sky9x/board.h
index 22e29abf9..c5b42359e 100644
--- a/radio/src/targets/sky9x/board.h
+++ b/radio/src/targets/sky9x/board.h
@@ -405,6 +405,7 @@ void rxPdcUsart( void (*pChProcess)(uint8_t x) );
 
 // Second UART driver
 void serial2TelemetryInit(unsigned int protocol);
+void serial2Putc(const unsigned char c);
 #if defined(__cplusplus)
 bool telemetrySecondPortReceive(uint8_t & data);
 #endif
diff --git a/radio/src/targets/sky9x/serial2_driver.cpp b/radio/src/targets/sky9x/serial2_driver.cpp
index 3f2153f1a..b7a749ff7 100644
--- a/radio/src/targets/sky9x/serial2_driver.cpp
+++ b/radio/src/targets/sky9x/serial2_driver.cpp
@@ -37,12 +37,12 @@ Fifo<uint8_t, 512> serial2RxFifo;
  * This function is synchronous (i.e. uses polling).
  * c  Character to send.
  */
-void serial2Putc(const char c)
+void serial2Putc(const unsigned char c)
 {
   Uart *pUart = SECOND_SERIAL_UART;
 
   /* Wait for the transmitter to be ready */
-  while ( (pUart->UART_SR & UART_SR_TXEMPTY) == 0 ) ;
+  while ( (pUart->UART_SR & UART_SR_TXRDY) == 0 ) ;
 
   /* Send character */
   pUart->UART_THR = c;
@@ -99,8 +99,12 @@ void SECOND_UART_Stop()
 
 extern "C" void UART0_IRQHandler()
 {
-  serial2RxFifo.push(SECOND_SERIAL_UART->UART_RHR);
+  if ( SECOND_SERIAL_UART->UART_SR & UART_SR_RXRDY )
+  {
+    serial2RxFifo.push(SECOND_SERIAL_UART->UART_RHR);
+  }
 }
+
 #else
 #define SECOND_UART_Configure(...)
 #endif
@@ -109,7 +113,6 @@ extern "C" void UART0_IRQHandler()
 void serial2TelemetryInit(unsigned int /*protocol*/)
 {
   SECOND_UART_Configure(FRSKY_D_BAUDRATE, Master_frequency);
-  // startPdcUsartReceive();
 }
 
 bool telemetrySecondPortReceive(uint8_t & data)
@@ -117,3 +120,7 @@ bool telemetrySecondPortReceive(uint8_t & data)
   return serial2RxFifo.pop(data);
 }
 #endif
+
+#if defined(DEBUG)
+void serialPrintf(const char*, ... ) {}
+#endif
diff --git a/radio/src/telemetry/telemetry.cpp b/radio/src/telemetry/telemetry.cpp
index a98befd45..41e19e9b9 100644
--- a/radio/src/telemetry/telemetry.cpp
+++ b/radio/src/telemetry/telemetry.cpp
@@ -404,7 +404,7 @@ void telemetryInit(uint8_t protocol)
   }
 #endif
 
-#if defined(SERIAL2)
+#if defined(SERIAL2) || defined(PCBSKY9X)
   else if (protocol == PROTOCOL_FRSKY_D_SECONDARY) {
     telemetryPortInit(0, TELEMETRY_SERIAL_DEFAULT);
     serial2TelemetryInit(PROTOCOL_FRSKY_D_SECONDARY);