Index: firmware/App/Services/SystemComm.c
===================================================================
diff -u -r6fc5e3596bfb7f27e93e4bfbe4909b9f58c17b48 -r1f3647830e9de0a1f0a4e445ce8d72d5525f51fb
--- firmware/App/Services/SystemComm.c	(.../SystemComm.c)	(revision 6fc5e3596bfb7f27e93e4bfbe4909b9f58c17b48)
+++ firmware/App/Services/SystemComm.c	(.../SystemComm.c)	(revision 1f3647830e9de0a1f0a4e445ce8d72d5525f51fb)
@@ -412,14 +412,20 @@
  *************************************************************************/
 static void transmitNextUARTPacket( void )
 {
-    U32 dataSize = getFromCommBuffer( COMM_BUFFER_OUT_UART_PC, pcXmitPacket, PC_MESSAGE_PACKET_SIZE );
+    U32 dataPend = numberOfBytesInCommBuffer( COMM_BUFFER_OUT_UART_PC );
+    U32 dataSize;
 
-    // if there's another UART packet to send, send it
-    if ( dataSize == PC_MESSAGE_PACKET_SIZE )
+    if ( dataPend >= PC_MESSAGE_PACKET_SIZE )
     {
-        dmaSetCtrlPacket( DMA_CH3, pcDMAXmitControlRecord );
-        dmaSetChEnable( DMA_CH3, DMA_HW );
-        setSCI1DMATransmitInterrupt();
+        dataSize = getFromCommBuffer( COMM_BUFFER_OUT_UART_PC, pcXmitPacket, PC_MESSAGE_PACKET_SIZE );
+
+        // if there's another UART packet to send, send it
+        if ( dataSize == PC_MESSAGE_PACKET_SIZE )
+        {
+            dmaSetCtrlPacket( DMA_CH3, pcDMAXmitControlRecord );
+            dmaSetChEnable( DMA_CH3, DMA_HW );
+            setSCI1DMATransmitInterrupt();
+        }
     }
 }