diff --git a/flight/Modules/Telemetry/telemetry.c b/flight/Modules/Telemetry/telemetry.c
index e0f8b2d5f..cf24ec12a 100644
--- a/flight/Modules/Telemetry/telemetry.c
+++ b/flight/Modules/Telemetry/telemetry.c
@@ -133,7 +133,7 @@ int32_t TelemetryInitialize(void)
 	updateSettings();
     
 	// Initialise UAVTalk
-	uavTalkCon = UAVTalkInitialize(&transmitData,256);
+	uavTalkCon = UAVTalkInitialize(&transmitData);
     
 	// Create periodic event that will be used to update the telemetry stats
 	txErrors = 0;
@@ -339,7 +339,8 @@ static void telemetryRxTask(void *parameters)
  * Transmit data buffer to the modem or USB port.
  * \param[in] data Data buffer to send
  * \param[in] length Length of buffer
- * \return 0 Success
+ * \return -1 on failure
+ * \return number of bytes transmitted on success
  */
 static int32_t transmitData(uint8_t * data, int32_t length)
 {
@@ -356,7 +357,7 @@ static int32_t transmitData(uint8_t * data, int32_t length)
 	}
 
 	if (outputPort) {
-		return PIOS_COM_SendBufferNonBlocking(outputPort, data, length);
+		return PIOS_COM_SendBuffer(outputPort, data, length);
 	} else {
 		return -1;
 	}
diff --git a/flight/UAVTalk/inc/uavtalk.h b/flight/UAVTalk/inc/uavtalk.h
index 71114ce74..3b7f2a2f9 100644
--- a/flight/UAVTalk/inc/uavtalk.h
+++ b/flight/UAVTalk/inc/uavtalk.h
@@ -46,7 +46,7 @@ typedef struct {
 typedef void* UAVTalkConnection;
 
 // Public functions
-UAVTalkConnection UAVTalkInitialize(UAVTalkOutputStream outputStream, uint32_t maxPacketSize);
+UAVTalkConnection UAVTalkInitialize(UAVTalkOutputStream outputStream);
 int32_t UAVTalkSetOutputStream(UAVTalkConnection connection, UAVTalkOutputStream outputStream);
 UAVTalkOutputStream UAVTalkGetOutputStream(UAVTalkConnection connection);
 int32_t UAVTalkSendObject(UAVTalkConnection connection, UAVObjHandle obj, uint16_t instId, uint8_t acked, int32_t timeoutMs);
diff --git a/flight/UAVTalk/uavtalk.c b/flight/UAVTalk/uavtalk.c
index 900dc24b3..844ed5e38 100644
--- a/flight/UAVTalk/uavtalk.c
+++ b/flight/UAVTalk/uavtalk.c
@@ -48,9 +48,8 @@ static void updateAck(UAVTalkConnectionData *connection, UAVObjHandle obj, uint1
  * \return 0 Success
  * \return -1 Failure
  */
-UAVTalkConnection UAVTalkInitialize(UAVTalkOutputStream outputStream, uint32_t maxPacketSize)
+UAVTalkConnection UAVTalkInitialize(UAVTalkOutputStream outputStream)
 {
-	if (maxPacketSize<1) return 0;
 	// allocate object
 	UAVTalkConnectionData * connection = pvPortMalloc(sizeof(UAVTalkConnectionData));
 	if (!connection) return 0;
@@ -60,7 +59,6 @@ UAVTalkConnection UAVTalkInitialize(UAVTalkOutputStream outputStream, uint32_t m
 	connection->outStream = outputStream;
 	connection->lock = xSemaphoreCreateRecursiveMutex();
 	connection->transLock = xSemaphoreCreateRecursiveMutex();
-	connection->txSize = maxPacketSize;
 	// allocate buffers
 	connection->rxBuffer = pvPortMalloc(UAVTALK_MAX_PACKET_LENGTH);
 	if (!connection->rxBuffer) return 0;
@@ -646,7 +644,9 @@ static int32_t sendSingleObject(UAVTalkConnectionData *connection, UAVObjHandle
 	int32_t length;
 	int32_t dataOffset;
 	uint32_t objId;
-	
+
+	if (!connection->outStream) return -1;
+
 	// Setup type and object id fields
 	objId = UAVObjGetID(obj);
 	connection->txBuffer[0] = UAVTALK_SYNC_VAL;  // sync byte
@@ -701,22 +701,16 @@ static int32_t sendSingleObject(UAVTalkConnectionData *connection, UAVObjHandle
 	// Calculate checksum
 	connection->txBuffer[dataOffset+length] = PIOS_CRC_updateCRC(0, connection->txBuffer, dataOffset+length);
 
-	// Send buffer (partially if needed)
-	uint32_t sent=0;
-	while (sent < dataOffset+length+UAVTALK_CHECKSUM_LENGTH) {
-		uint32_t sending = dataOffset+length+UAVTALK_CHECKSUM_LENGTH - sent;
-		if ( sending > connection->txSize ) sending = connection->txSize;
-		if ( connection->outStream != NULL ) {
-			(*connection->outStream)(connection->txBuffer+sent, sending);
-		}
-		sent += sending;
+	uint16_t tx_msg_len = dataOffset+length+UAVTALK_CHECKSUM_LENGTH;
+	int32_t rc = (*connection->outStream)(connection->txBuffer, tx_msg_len);
+
+	if (rc == tx_msg_len) {
+		// Update stats
+		++connection->stats.txObjects;
+		connection->stats.txBytes += tx_msg_len;
+		connection->stats.txObjectBytes += length;
 	}
 	
-	// Update stats
-	++connection->stats.txObjects;
-	connection->stats.txBytes += dataOffset+length+UAVTALK_CHECKSUM_LENGTH;
-	connection->stats.txObjectBytes += length;
-	
 	// Done
 	return 0;
 }
@@ -732,6 +726,8 @@ static int32_t sendNack(UAVTalkConnectionData *connection, uint32_t objId)
 {
 	int32_t dataOffset;
 
+	if (!connection->outStream) return -1;
+
 	connection->txBuffer[0] = UAVTALK_SYNC_VAL;  // sync byte
 	connection->txBuffer[1] = UAVTALK_TYPE_NACK;
 	// data length inserted here below
@@ -749,11 +745,13 @@ static int32_t sendNack(UAVTalkConnectionData *connection, uint32_t objId)
 	// Calculate checksum
 	connection->txBuffer[dataOffset] = PIOS_CRC_updateCRC(0, connection->txBuffer, dataOffset);
 
-	// Send buffer
-	if (connection->outStream!=NULL) (*connection->outStream)(connection->txBuffer, dataOffset+UAVTALK_CHECKSUM_LENGTH);
+	uint16_t tx_msg_len = dataOffset+UAVTALK_CHECKSUM_LENGTH;
+	int32_t rc = (*connection->outStream)(connection->txBuffer, tx_msg_len);
 
-	// Update stats
-	connection->stats.txBytes += dataOffset+UAVTALK_CHECKSUM_LENGTH;
+	if (rc == tx_msg_len) {
+		// Update stats
+		connection->stats.txBytes += tx_msg_len;
+	}
 
 	// Done
 	return 0;