Index: firmware/App/Services/SystemComm.c
===================================================================
diff -u -rb6416214042da75dfa311b726e401442b34315d7 -rc50cda7ff8b7d95c3daddce2c66904934b069a9d
--- firmware/App/Services/SystemComm.c	(.../SystemComm.c)	(revision b6416214042da75dfa311b726e401442b34315d7)
+++ firmware/App/Services/SystemComm.c	(.../SystemComm.c)	(revision c50cda7ff8b7d95c3daddce2c66904934b069a9d)
@@ -49,8 +49,8 @@
 #define MAX_COMM_CRC_FAILURES           5                                   ///< maximum number of CRC errors within window period before alarm
 #define MAX_COMM_CRC_FAILURE_WINDOW_MS  (10 * SEC_PER_MIN * MS_PER_SECOND)  ///< CRC error window
 
-#define MSG_NOT_ACKED_TIMEOUT_MS        150                                 ///< maximum time for a Denali message that requires ACK to be ACK'd
-#define MSG_NOT_ACKED_MAX_RETRIES       8                                   ///< maximum number of times a message that requires ACK that was not ACK'd can be re-sent before alarm
+#define MSG_NOT_ACKED_TIMEOUT_MS        250                                 ///< maximum time for a Denali message that requires ACK to be ACK'd
+#define MSG_NOT_ACKED_MAX_RETRIES       10                                   ///< maximum number of times a message that requires ACK that was not ACK'd can be re-sent before alarm
 #define PENDING_ACK_LIST_SIZE           25                                  ///< maximum number of Delanli messages that can be pending ACK at any given time
 
 #define MAX_FPGA_CLOCK_SPEED_ERRORS             3                           ///< maximum number of FPGA clock speed errors within window period before alarm
@@ -770,27 +770,41 @@
     U32  i;
 
     // find expired messages pending ACK
-    for ( i = 0; i < PENDING_ACK_LIST_SIZE; i++ )
-    {   // pending ACK expired?
-        if ( ( TRUE == pendingAckList[ i ].used ) && ( TRUE == didTimeout( pendingAckList[ i ].timeStamp, MSG_NOT_ACKED_TIMEOUT_MS ) ) )
-        {   // if retries left, reset and resend pending message. Do not retry when in POST since the UI might not still be responsive
-            if ( ( pendingAckList[ i ].retries > 0 ) && ( getCurrentOperationMode() != DG_MODE_INIT ) )
-            {   // re-queue message for transmit
-                pendingAckList[ i ].retries--;
-                pendingAckList[ i ].timeStamp = getMSTimerCount();
-                addToCommBuffer( pendingAckList[ i ].channel, pendingAckList[ i ].msg, pendingAckList[ i ].msgSize );
-            }
-            // if no retries left, alarm
-            else
-            {
-                U16 msgID;
+    if( TRUE == isHDCommunicating() )
+    {
+        for ( i = 0; i < PENDING_ACK_LIST_SIZE; i++ )
+        {   // pending ACK expired?
+            if ( ( TRUE == pendingAckList[ i ].used ) && ( TRUE == didTimeout( pendingAckList[ i ].timeStamp, MSG_NOT_ACKED_TIMEOUT_MS ) ) )
+            {   // if retries left, reset and resend pending message. Do not retry when in POST since the UI might not still be responsive
+                if ( pendingAckList[ i ].retries > 0 )
+                {
+                    if ( getCurrentOperationMode() != DG_MODE_INIT )
+                    {   // If not in post, limit the number of retries
+                        pendingAckList[ i ].retries--;
+                    }
+                    // Resend message
+                    pendingAckList[ i ].timeStamp = getMSTimerCount();
+                    addToCommBuffer( pendingAckList[ i ].channel, pendingAckList[ i ].msg, pendingAckList[ i ].msgSize );
+                }
+                // if no retries left, alarm
+                else
+                {
+                    U16 msgID;
 
-                memcpy( &msgID, &pendingAckList[ i ].msg[ sizeof( U08 ) + sizeof( U16 ) ], sizeof( U16 ) );
-                SET_ALARM_WITH_1_U32_DATA( ALARM_ID_DG_CAN_MESSAGE_NOT_ACKED, (U32)msgID );
-                pendingAckList[ i ].used = FALSE;  // take pending message off of list
+                    memcpy( &msgID, &pendingAckList[ i ].msg[ sizeof( U08 ) + sizeof( U16 ) ], sizeof( U16 ) );
+                    SET_ALARM_WITH_1_U32_DATA( ALARM_ID_DG_CAN_MESSAGE_NOT_ACKED, (U32)msgID );
+                    pendingAckList[ i ].used = FALSE;  // take pending message off of list
+                }
             }
         }
     }
+    else
+    {   // Clear pending ACK list
+        for ( i = 0; i < PENDING_ACK_LIST_SIZE; i++ )
+        {
+            pendingAckList[ i ].used = FALSE;
+        }
+    }
 }
 
 /*********************************************************************//**