Index: firmware/App/Modes/FPModes/FPOperationModes.c
===================================================================
diff -u -r89c8709e3b27648926fbb20f25c9a67cbeb99adc -r336f6c49e05f515ca1250e0fd9ea97e5f5b5f11c
--- firmware/App/Modes/FPModes/FPOperationModes.c	(.../FPOperationModes.c)	(revision 89c8709e3b27648926fbb20f25c9a67cbeb99adc)
+++ firmware/App/Modes/FPModes/FPOperationModes.c	(.../FPOperationModes.c)	(revision 336f6c49e05f515ca1250e0fd9ea97e5f5b5f11c)
@@ -7,8 +7,8 @@
 *
 * @file    FPOperationModes.c
 *
-* @author  (last)      “rkallala”
-* @date    (last)      15-Jan-2026
+* @author  (last)      Michael Garthwaite
+* @date    (last)      17-Apr-2026
 *
 * @author  (original)  Michael Garthwaite
 * @date    (original)  08-Sep-2025
@@ -49,6 +49,8 @@
 static U32 current4thLevelState;                                                ///< current 4th level state.
 static BOOL isDeviceDefeatured;                                                 ///< bool to determine defeatured status
 static BOOL isBoostInstalled;                                                   ///< bool to determine boost pump status
+static U32 testRequestedSubMode;                                                ///< Requested operation sub mode from dialin.
+static BOOL testChangeSubMode;                                                  ///< Flag to determine change operation sub mode request status.
 
 /// Interval (in task intervals) at which to publish operation mode data to CAN bus.
 static OVERRIDE_U32_T opModePublishInterval = { BROADCAST_TD_OP_MODE_INTERVAL, BROADCAST_TD_OP_MODE_INTERVAL, BROADCAST_TD_OP_MODE_INTERVAL, 0 };
@@ -70,6 +72,8 @@
 static FP_OP_MODE_T arbitrateModeRequest( void );
 static void transitionToNewOperationMode( FP_OP_MODE_T newMode );
 static void broadcastOperationMode( void );
+static void testRequestNewFPOperationSubMode( void );
+static BOOL testValidateSubModeChangeRequest( FP_OP_MODE_T reqMode, U32 reqSubMode );
 
 /*********************************************************************//**
  * @brief
@@ -97,6 +101,8 @@
     broadcastModeIntervalCtr = DATA_PUBLISH_COUNTER_START_COUNT;
     isDeviceDefeatured       = FALSE;
     isBoostInstalled         = FALSE;
+    testRequestedSubMode     = 0;
+    testChangeSubMode        = FALSE;
 
     transitionToNewOperationMode( FP_MODE_INIT );
 
@@ -126,10 +132,15 @@
 
     // Any new mode requests?
     newMode = arbitrateModeRequest();   // Will return current mode if no pending requests
-    newMode = MODE_TRANSITION_TABLE[ currentMode ][ newMode ];
 
+    if ( isTestingActivated() != TRUE )
+    {
+        // if the test configuration is not enabled check for the legality of the transition request
+        newMode = MODE_TRANSITION_TABLE[ currentMode ][ newMode ];
+    }
+
     // Is requested new mode valid and legal at this time?
-    if ( ( newMode >= FP_MODE_NLEG ) && ( isTestingActivated() != TRUE ) )
+    if ( newMode >= FP_MODE_NLEG )
     {
         SET_ALARM_WITH_2_U32_DATA( ALARM_ID_FP_SOFTWARE_FAULT, FP_FAULT_ID_OP_MODES_ILLEGAL_MODE_TRANSITION_REQUESTED, newMode )
         newMode = currentMode;
@@ -144,6 +155,12 @@
         currentMode = newMode;
 //        sendOperationStatusEvent();
     }
+    // Is sub mode change request active?
+    if ( TRUE == testChangeSubMode )
+    {
+        testChangeSubMode = FALSE;
+        testRequestNewFPOperationSubMode();
+    }
 
     // Mode specific processing to be done continuously
     switch ( currentMode )
@@ -177,7 +194,7 @@
             break;
 
         case FP_MODE_DEGP:
-            currentSubMode = execPreGenPMode();
+            currentSubMode = execGenPermeateDefeaturedMode();
             break;
 
         default:
@@ -403,11 +420,22 @@
  * @brief
  * The isFPDefeatured function returns if the Leahi device is defeatured.
  * @details \b Inputs: none
- * @details \b Outputs: none
+ * @details \b Outputs: isDeviceDefeatured
  * @return TRUE if FP device is de-featured, FALSE if not.
  *************************************************************************/
 BOOL isFPDefeatured( void )
 {
+    // TODO decide whether we need this test config even after NVM is defined
+    if ( TRUE == getTestConfigStatus( TEST_CONFIG_FP_ENABLE_DEFEATURE ) )
+    {
+        isDeviceDefeatured = TRUE;
+    }
+    // TODO remove the else if after NVM implementation. Value is read from NV memory no need to reset
+    else if ( TRUE != getTestConfigStatus( TEST_CONFIG_FP_ENABLE_DEFEATURE ) )
+    {
+        isDeviceDefeatured = FALSE;
+    }
+
     // TODO - pull status from NV mem.
     return isDeviceDefeatured;
 }
@@ -417,11 +445,22 @@
  * The isBoostPumpInstalled function returns if the Leahi device
  * has a boost pump installed.
  * @details \b Inputs: none
- * @details \b Outputs: none
+ * @details \b Outputs: isBoostInstalled
  * @return TRUE if FP device is contains a boost pump, FALSE if not.
  *************************************************************************/
 BOOL isBoostPumpInstalled( void )
 {
+    // TODO decide whether we need this test config even after NVM is defined
+    if ( TRUE == getTestConfigStatus( TEST_CONFIG_FP_ENABLE_BOOST_PUMP ) )
+    {
+        isBoostInstalled = TRUE;
+    }
+    // TODO remove the else if after NVM implementation. Value is read from NV memory no need to reset
+    else if ( TRUE != getTestConfigStatus( TEST_CONFIG_FP_ENABLE_BOOST_PUMP ) )
+    {
+        isBoostInstalled = FALSE;
+    }
+
     // TODO - pull status from NV mem.
     return isBoostInstalled;
 }
@@ -597,4 +636,175 @@
     return result;
 }
 
+/*********************************************************************//**
+ * @brief
+ * The testGetFPBoostPumpInstallStatus function return whether FP Boost Pump
+ * is installed or not.
+ * @details \b Inputs: none
+ * @details \b Outputs: none
+ * @details \b Message: \b Sent: MSG_ID_FP_BOOST_PUMP_INSTALL_STATUS_RESPONSE
+ * @param message request message from Dialin for FP boost pump install status.
+ * @return TRUE if request is successful, FALSE if not
+ *************************************************************************/
+BOOL testGetFPBoostPumpInstallStatus( MESSAGE_T *message )
+{
+    BOOL result = FALSE;
+    FP_BOOST_PUMP_INSTALL_STATUS_PAYLOAD_T data;
+
+    data.isFPBoostPumpInstalled = isBoostPumpInstalled();
+    result = sendMessage( MSG_ID_FP_BOOST_PUMP_INSTALL_STATUS_RESPONSE, COMM_BUFFER_OUT_DD_CAN_PC, (U08*)&data, sizeof(FP_BOOST_PUMP_INSTALL_STATUS_PAYLOAD_T) );
+
+    return result;
+}
+
+/*********************************************************************//**
+ * @brief
+ * The testSetFPOperationSubMode function will transition to a given
+ * sub mode if the transition is legal.
+ * @details \b Inputs: currentMode, currentSubMode
+ * @details \b Outputs: modeRequest[], testRequestedSubMode, testChangeSubMode
+ * @param message message from Dialin which includes the sub mode to
+ * transition to.
+ * @return TRUE if request successful, FALSE if not
+ *************************************************************************/
+BOOL testSetFPOperationSubMode( MESSAGE_T *message )
+{
+    OP_MODE_PAYLOAD_T payload;
+    BOOL result = FALSE;
+
+    // Verify message payload length is valid
+    if ( sizeof( OP_MODE_PAYLOAD_T ) == message->hdr.payloadLen )
+    {
+        FP_OP_MODE_T reqMode;
+        U32 reqSubMode;
+
+        memcpy( (U08*)(&payload), message->payload, sizeof( OP_MODE_PAYLOAD_T ) );
+
+        reqMode = (FP_OP_MODE_T)payload.opMode;
+        reqSubMode = payload.subMode;
+
+        if ( reqMode < NUM_OF_FP_MODES )
+        {
+            // verify if the requested submode transition is possible
+            result = testValidateSubModeChangeRequest( reqMode, reqSubMode );
+
+            // send the sub mode change request only if the requested transition is valid
+            if ( TRUE == result )
+            {
+                // request new operation mode and sub mode if the requested operation mode is not current mode
+                if ( currentMode != reqMode )
+                {
+                    requestNewFPOperationMode( reqMode );
+                    testRequestedSubMode = reqSubMode;
+                    testChangeSubMode = TRUE;
+                }
+                // request submode change only as the requested operation mode is current mode and requested sub mode is not current sub mode
+                else if ( currentSubMode != reqSubMode )
+                {
+                    testRequestedSubMode = reqSubMode;
+                    testChangeSubMode = TRUE;
+                }
+            }
+        }
+    }
+
+    return result;
+}
+
+/*********************************************************************//**
+ * @brief
+ * The testValidateSubModeChangeRequest function validates the
+ * requested sub mode change is acceptable or not.
+ * operation sub mode.
+ * @details \b Inputs: none
+ * @details \b Outputs: none
+ * @param reqMode FP operation mode enumeration
+ * @param reqSubMode operation sub mode requested
+ * @return TRUE if request is legal, FALSE if not.
+ *************************************************************************/
+static BOOL testValidateSubModeChangeRequest( FP_OP_MODE_T reqMode, U32 reqSubMode )
+{
+    BOOL result = FALSE;
+
+    switch ( reqMode )
+    {
+        case FP_MODE_PGEN:
+            result = testValidatePreGenPChangeReq( reqSubMode );
+            break;
+
+        case FP_MODE_GENP:
+            result = testValidateGenPermeateChangeReq( reqSubMode );
+            break;
+
+        case FP_MODE_DPGP:
+            result = testValidatePreGenPDefeaturedChangeReq( reqSubMode );
+            break;
+
+        case FP_MODE_DEGP:
+            result = testValidateGenPDefeaturedChangeReq( reqSubMode );
+            break;
+
+        case FP_MODE_FAUL:
+            result = testValidateFaultChangeReq( reqSubMode );
+            break;
+
+        case FP_MODE_STAN:
+            result = testValidateStandbyChangeReq( reqSubMode );
+            break;
+
+        // No need to validate the request for the following modes as it is not supported
+        case FP_MODE_SERV:
+        case FP_MODE_INIT:
+        default:
+            // result is already FALSE. Do nothing for modes that do not support jump to sub-mode
+            break;
+    }
+
+    return result;
+}
+
+/*********************************************************************//**
+ * @brief
+ * The testRequestNewFPOperationSubMode function requests transition to a new
+ * operation sub mode.
+ * @details \b Inputs: currentMode, testRequestedSubMode
+ * @details \b Outputs: none
+ * @return none
+ *************************************************************************/
+static void testRequestNewFPOperationSubMode( void )
+{
+    switch ( currentMode )
+    {
+        case FP_MODE_PGEN:
+            testSignalNewPreGenPSubMode( testRequestedSubMode );
+            break;
+
+        case FP_MODE_GENP:
+            testSignalNewGenPermeateSubMode( testRequestedSubMode );
+            break;
+
+        case FP_MODE_DPGP:
+            testSignalNewPreGenPDefeaturedSubMode( testRequestedSubMode );
+            break;
+
+        case FP_MODE_DEGP:
+            testSignalNewGenPDefeaturedSubMode( testRequestedSubMode );
+            break;
+
+        case FP_MODE_FAUL:
+            testSignalNewFaultSubMode( testRequestedSubMode );
+            break;
+
+        case FP_MODE_STAN:
+            testSignalNewStandbySubMode( testRequestedSubMode );
+            break;
+
+        case FP_MODE_SERV:
+        case FP_MODE_INIT:
+        default:
+            // do nothing for modes that do not support jump to sub-mode
+            break;
+    }
+}
+
 /**@}*/