diff --git a/mtce-common/src/common/nodeBase.h b/mtce-common/src/common/nodeBase.h
index 8af83c3b..38a188d7 100755
--- a/mtce-common/src/common/nodeBase.h
+++ b/mtce-common/src/common/nodeBase.h
@@ -66,7 +66,7 @@ void daemon_exit ( void );
 #define FAIL_BM_IPADDR              (121*256)
 #define FAIL_BM_PASSWORD            (122*256)
 
-
+#define MTC_PARM_LOCK_PERSIST_IDX   (0) // node lock command
 #define MTC_PARM_UPTIME_IDX (0)
 #define MTC_PARM_HEALTH_IDX (1)
 #define MTC_PARM_FLAGS_IDX  (2)
@@ -110,6 +110,7 @@ void daemon_exit ( void );
 #define SMGMT_DEGRADED_FILE     ((const char *)"/var/run/.sm_degraded")
 #define SMGMT_UNHEALTHY_FILE    ((const char *)"/var/run/.sm_node_unhealthy")
 #define UNLOCK_READY_FILE       ((const char *)"/etc/platform/.unlock_ready")
+#define STILL_SIMPLEX_FILE      ((const char *)"/etc/platform/simplex")
 
 /** path to and module init file name */
 #define MTCE_CONF_FILE          ((const char *)"/etc/mtc.conf")
diff --git a/mtce/src/maintenance/mtcCompMsg.cpp b/mtce/src/maintenance/mtcCompMsg.cpp
index ba6049ba..446f1f53 100755
--- a/mtce/src/maintenance/mtcCompMsg.cpp
+++ b/mtce/src/maintenance/mtcCompMsg.cpp
@@ -237,13 +237,20 @@ int mtc_service_command ( mtc_socket_type * sock_ptr, int interface )
                 daemon_log ( NODE_LOCKED_FILE, ADMIN_LOCKED_STR);
             }
 
-            /* Preserve the node locked state in a non-volatile backup
-             * file that persists over reboot.
-             * Maintaining the legacy NODE_LOCKED_FILE as other sw looks at it. */
-            if ( daemon_is_file_present ( NODE_LOCKED_FILE_BACKUP ) == false )
+            /* Only create the non-volatile NODE_LOCKED_FILE_BACKUP file if the
+             * LOCK_PERSIST flag is present. */
+            if ( msg.num && msg.parm[MTC_PARM_LOCK_PERSIST_IDX] )
             {
-                daemon_log ( NODE_LOCKED_FILE_BACKUP, ADMIN_LOCKED_STR );
+                /* Preserve the node locked state in a non-volatile backup
+                 * file that persists over reboot.
+                 * Maintaining the legacy NODE_LOCKED_FILE as other sw looks at it. */
+                if ( daemon_is_file_present ( NODE_LOCKED_FILE_BACKUP ) == false )
+                    daemon_log ( NODE_LOCKED_FILE_BACKUP, ADMIN_LOCKED_STR );
             }
+            /* Otherwise if we get a locked message without the LOCK_PERSIST flag
+             * then remove the non-volatile NODE_LOCKED_FILE_BACKUP file if exists */
+            else if ( daemon_is_file_present ( NODE_LOCKED_FILE_BACKUP ) == true )
+                daemon_remove_file ( NODE_LOCKED_FILE_BACKUP );
         }
         else if ( msg.cmd == MTC_MSG_UNLOCKED )
         {
diff --git a/mtce/src/maintenance/mtcCtrlMsg.cpp b/mtce/src/maintenance/mtcCtrlMsg.cpp
index 69fef347..1b1ccb5c 100755
--- a/mtce/src/maintenance/mtcCtrlMsg.cpp
+++ b/mtce/src/maintenance/mtcCtrlMsg.cpp
@@ -717,6 +717,20 @@ int send_mtc_cmd ( string & hostname, int cmd , int interface, string json_dict
             snprintf ( &mtc_cmd.hdr[0], MSG_HEADER_SIZE, "%s", get_cmd_req_msg_header() );
             mtc_cmd.cmd = cmd ;
             mtc_cmd.num = 0 ;
+            /* Only set the LOCK_PERSIST flag if the STILL_SIMPLEX_FILE
+             * is no longer present.
+             *
+             * The mtcClient will NOT create the non-volatile
+             * NODE_LOCKED_FILE_BACKUP file if the LOCK_PERSIST flag
+             * is missing.
+             *
+             * This way SM won't shutdown or prevent activating on a
+             * locked controller until the system is truely duplex. */
+            if ( daemon_is_file_present ( STILL_SIMPLEX_FILE ) == false )
+            {
+                mtc_cmd.num = 1 ;
+                mtc_cmd.parm[MTC_PARM_LOCK_PERSIST_IDX] = true ;
+            }
             rc = PASS ;
             break ;
         }