Index: firmware/App/Modes/Prime.c
===================================================================
diff -u -r8f0292d944c1796f8f246bec5692a9b295be3ac2 -r75e1ae332d1446dddf9b8d4ce6e8317449c57d67
--- firmware/App/Modes/Prime.c	(.../Prime.c)	(revision 8f0292d944c1796f8f246bec5692a9b295be3ac2)
+++ firmware/App/Modes/Prime.c	(.../Prime.c)	(revision 75e1ae332d1446dddf9b8d4ce6e8317449c57d67)
@@ -7,8 +7,8 @@
 *
 * @file    Prime.c
 *
-* @author  (last)      Dara Navaei
-* @date    (last)      22-Dec-2022
+* @author  (last)      Michael Garthwaite
+* @date    (last)      19-Jan-2023
 *
 * @author  (original)  Quang Nguyen
 * @date    (original)  08-Dec-2020
@@ -223,6 +223,8 @@
  *************************************************************************/
 void execPrime( void )
 {
+    HD_PRE_TREATMENT_PRIME_STATE_T priorSubState = currentPrimeState;
+
     // execute prime sub-mode state machine
     switch ( currentPrimeState )
     {
@@ -286,6 +288,11 @@
     // Prime flags should be handled by now
     resetPrimeFlags();
 
+    if ( priorSubState != currentPrimeState )
+    {
+        SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentPrimeState );
+    }
+
     // Broadcast priming data
     broadcastPrimingStatus();
 }