diff --git a/flight/UAVTalk/inc/uavtalk.h b/flight/UAVTalk/inc/uavtalk.h
index 3b7f2a2f9..f4616ae7d 100644
--- a/flight/UAVTalk/inc/uavtalk.h
+++ b/flight/UAVTalk/inc/uavtalk.h
@@ -45,13 +45,15 @@ typedef struct {
 
 typedef void* UAVTalkConnection;
 
+typedef enum {UAVTALK_STATE_ERROR=0, UAVTALK_STATE_SYNC, UAVTALK_STATE_TYPE, UAVTALK_STATE_SIZE, UAVTALK_STATE_OBJID, UAVTALK_STATE_INSTID, UAVTALK_STATE_DATA, UAVTALK_STATE_CS, UAVTALK_STATE_COMPLETE} UAVTalkRxState;
+
 // Public functions
 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);
 int32_t UAVTalkSendObjectRequest(UAVTalkConnection connection, UAVObjHandle obj, uint16_t instId, int32_t timeoutMs);
-int32_t UAVTalkProcessInputStream(UAVTalkConnection connection, uint8_t rxbyte);
+UAVTalkRxState UAVTalkProcessInputStream(UAVTalkConnection connection, uint8_t rxbyte);
 void UAVTalkGetStats(UAVTalkConnection connection, UAVTalkStats *stats);
 void UAVTalkResetStats(UAVTalkConnection connection);
 
diff --git a/flight/UAVTalk/inc/uavtalk_priv.h b/flight/UAVTalk/inc/uavtalk_priv.h
index 77863a6a8..992bf91af 100644
--- a/flight/UAVTalk/inc/uavtalk_priv.h
+++ b/flight/UAVTalk/inc/uavtalk_priv.h
@@ -55,8 +55,6 @@ typedef uint8_t uavtalk_checksum;
 #define UAVTALK_MIN_PACKET_LENGTH	UAVTALK_MAX_HEADER_LENGTH + UAVTALK_CHECKSUM_LENGTH
 #define UAVTALK_MAX_PACKET_LENGTH       UAVTALK_MIN_PACKET_LENGTH + UAVTALK_MAX_PAYLOAD_LENGTH
 
-typedef enum {UAVTALK_STATE_SYNC, UAVTALK_STATE_TYPE, UAVTALK_STATE_SIZE, UAVTALK_STATE_OBJID, UAVTALK_STATE_INSTID, UAVTALK_STATE_DATA, UAVTALK_STATE_CS} UAVTalkRxState;
-
 typedef struct {
     UAVObjHandle obj;
     uint8_t type;
diff --git a/flight/UAVTalk/uavtalk.c b/flight/UAVTalk/uavtalk.c
index 844ed5e38..fe4593f93 100644
--- a/flight/UAVTalk/uavtalk.c
+++ b/flight/UAVTalk/uavtalk.c
@@ -252,10 +252,9 @@ static int32_t objectTransaction(UAVTalkConnectionData *connection, UAVObjHandle
  * Process an byte from the telemetry stream.
  * \param[in] connection UAVTalkConnection to be used
  * \param[in] rxbyte Received byte
- * \return 0 Success
- * \return -1 Failure
+ * \return UAVTalkRxState
  */
-int32_t UAVTalkProcessInputStream(UAVTalkConnection connectionHandle, uint8_t rxbyte)
+UAVTalkRxState UAVTalkProcessInputStream(UAVTalkConnection connectionHandle, uint8_t rxbyte)
 {
 	UAVTalkConnectionData *connection;
     CHECKCONHANDLE(connectionHandle,connection,return -1);
@@ -265,6 +264,9 @@ int32_t UAVTalkProcessInputStream(UAVTalkConnection connectionHandle, uint8_t rx
 	
 	if (iproc->rxPacketLength < 0xffff)
 		iproc->rxPacketLength++;   // update packet byte count
+
+	if (iproc->state == UAVTALK_STATE_ERROR || iproc->state == UAVTALK_STATE_COMPLETE)
+		iproc->state = UAVTALK_STATE_SYNC;
 	
 	// Receive state machine
 	switch (iproc->state)
@@ -288,7 +290,7 @@ int32_t UAVTalkProcessInputStream(UAVTalkConnection connectionHandle, uint8_t rx
 			
 			if ((rxbyte & UAVTALK_TYPE_MASK) != UAVTALK_TYPE_VER)
 			{
-				iproc->state = UAVTALK_STATE_SYNC;
+				iproc->state = UAVTALK_STATE_ERROR;
 				break;
 			}
 			
@@ -316,7 +318,7 @@ int32_t UAVTalkProcessInputStream(UAVTalkConnection connectionHandle, uint8_t rx
 			
 			if (iproc->packet_size < UAVTALK_MIN_HEADER_LENGTH || iproc->packet_size > UAVTALK_MAX_HEADER_LENGTH + UAVTALK_MAX_PAYLOAD_LENGTH)
 			{   // incorrect packet size
-				iproc->state = UAVTALK_STATE_SYNC;
+				iproc->state = UAVTALK_STATE_ERROR;
 				break;
 			}
 			
@@ -334,18 +336,8 @@ int32_t UAVTalkProcessInputStream(UAVTalkConnection connectionHandle, uint8_t rx
 
 			if (iproc->rxCount < 4)
 				break;
-			
-			// Search for object, if not found reset state machine
-			// except if we got a OBJ_REQ for an object which does not
-			// exist, in which case we'll send a NACK
 
 			iproc->obj = UAVObjGetByID(iproc->objId);
-			if (iproc->obj == 0 && iproc->type != UAVTALK_TYPE_OBJ_REQ)
-			{
-				connection->stats.rxErrors++;
-				iproc->state = UAVTALK_STATE_SYNC;
-				break;
-			}
 			
 			// Determine data length
 			if (iproc->type == UAVTALK_TYPE_OBJ_REQ || iproc->type == UAVTALK_TYPE_ACK || iproc->type == UAVTALK_TYPE_NACK)
@@ -355,15 +347,24 @@ int32_t UAVTalkProcessInputStream(UAVTalkConnection connectionHandle, uint8_t rx
 			}
 			else
 			{
-				iproc->length = UAVObjGetNumBytes(iproc->obj);
-				iproc->instanceLength = (UAVObjIsSingleInstance(iproc->obj) ? 0 : 2);
+				if (iproc->obj)
+				{
+					iproc->length = UAVObjGetNumBytes(iproc->obj);
+					iproc->instanceLength = (UAVObjIsSingleInstance(iproc->obj) ? 0 : 2);
+				}
+				else
+				{
+					// We don't know if it's a multi-instance object, so just assume it's 0.
+					iproc->instanceLength = 0;
+					iproc->length = iproc->packet_size - iproc->rxPacketLength;
+				}
 			}
 			
 			// Check length and determine next state
 			if (iproc->length >= UAVTALK_MAX_PAYLOAD_LENGTH)
 			{
 				connection->stats.rxErrors++;
-				iproc->state = UAVTALK_STATE_SYNC;
+				iproc->state = UAVTALK_STATE_ERROR;
 				break;
 			}
 			
@@ -371,20 +372,19 @@ int32_t UAVTalkProcessInputStream(UAVTalkConnection connectionHandle, uint8_t rx
 			if ((iproc->rxPacketLength + iproc->instanceLength + iproc->length) != iproc->packet_size)
 			{   // packet error - mismatched packet size
 				connection->stats.rxErrors++;
-				iproc->state = UAVTALK_STATE_SYNC;
+				iproc->state = UAVTALK_STATE_ERROR;
 				break;
 			}
 			
 			iproc->instId = 0;
-			if (iproc->obj == 0)
+			if (iproc->type == UAVTALK_TYPE_NACK)
 			{
 				// If this is a NACK, we skip to Checksum
 				iproc->state = UAVTALK_STATE_CS;
 				iproc->rxCount = 0;
-
 			}
 			// Check if this is a single instance object (i.e. if the instance ID field is coming next)
-			else if (UAVObjIsSingleInstance(iproc->obj))
+			else if ((iproc->obj == 0) || !UAVObjIsSingleInstance(iproc->obj))
 			{
 				// If there is a payload get it, otherwise receive checksum
 				if (iproc->length > 0)
@@ -441,33 +441,37 @@ int32_t UAVTalkProcessInputStream(UAVTalkConnection connectionHandle, uint8_t rx
 			if (rxbyte != iproc->cs)
 			{   // packet error - faulty CRC
 				connection->stats.rxErrors++;
-				iproc->state = UAVTALK_STATE_SYNC;
+				iproc->state = UAVTALK_STATE_ERROR;
 				break;
 			}
 			
 			if (iproc->rxPacketLength != (iproc->packet_size + 1))
 			{   // packet error - mismatched packet size
 				connection->stats.rxErrors++;
-				iproc->state = UAVTALK_STATE_SYNC;
+				iproc->state = UAVTALK_STATE_ERROR;
 				break;
 			}
-			
-			xSemaphoreTakeRecursive(connection->lock, portMAX_DELAY);
-			receiveObject(connection, iproc->type, iproc->objId, iproc->instId, connection->rxBuffer, iproc->length);
-			connection->stats.rxObjectBytes += iproc->length;
-			connection->stats.rxObjects++;
-			xSemaphoreGiveRecursive(connection->lock);
-			
-			iproc->state = UAVTALK_STATE_SYNC;
+
+			if (iproc->obj)
+			{
+				xSemaphoreTakeRecursive(connection->lock, portMAX_DELAY);
+				receiveObject(connection, iproc->type, iproc->objId, iproc->instId, connection->rxBuffer, iproc->length);
+				connection->stats.rxObjectBytes += iproc->length;
+				connection->stats.rxObjects++;
+				xSemaphoreGiveRecursive(connection->lock);
+			}
+
+			iproc->state = UAVTALK_STATE_COMPLETE;
 			break;
 			
 		default:
 			connection->stats.rxErrors++;
-			iproc->state = UAVTALK_STATE_SYNC;
+			iproc->state = UAVTALK_STATE_ERROR;
+			break;
 	}
 	
 	// Done
-	return 0;
+	return iproc->state;
 }
 
 /**