diff --git a/src/iec61850/inc_private/mms_mapping_internal.h b/src/iec61850/inc_private/mms_mapping_internal.h
index 3e896495..95727449 100644
--- a/src/iec61850/inc_private/mms_mapping_internal.h
+++ b/src/iec61850/inc_private/mms_mapping_internal.h
@@ -325,7 +325,10 @@ struct sMmsMapping {
     /* flag indicates if data model is locked --> prevents reports to be sent */
 
     bool isModelLocked;
+
+#if (CONFIG_MMS_THREADLESS_STACK != 1)
     Semaphore isModelLockedMutex;
+#endif /* (CONFIG_MMS_THREADLESS_STACK != 1) */
 
     IedServer iedServer;
 
diff --git a/src/iec61850/server/impl/ied_server.c b/src/iec61850/server/impl/ied_server.c
index f09e42b2..0253bcf1 100644
--- a/src/iec61850/server/impl/ied_server.c
+++ b/src/iec61850/server/impl/ied_server.c
@@ -814,11 +814,15 @@ IedServer_lockDataModel(IedServer self)
 {
     MmsServer_lockModel(self->mmsServer);
 
+#if (CONFIG_MMS_THREADLESS_STACK != 1)
     Semaphore_wait(self->mmsMapping->isModelLockedMutex);
+#endif
 
     self->mmsMapping->isModelLocked = true;
 
+#if (CONFIG_MMS_THREADLESS_STACK != 1)
     Semaphore_post(self->mmsMapping->isModelLockedMutex);
+#endif
 }
 
 void
@@ -832,13 +836,17 @@ IedServer_unlockDataModel(IedServer self)
     /* check if reports have to be sent! */
     Reporting_processReportEventsAfterUnlock(self->mmsMapping);
 
+#if (CONFIG_MMS_THREADLESS_STACK != 1)
     Semaphore_wait(self->mmsMapping->isModelLockedMutex);
+#endif
 
     MmsServer_unlockModel(self->mmsServer);
 
     self->mmsMapping->isModelLocked = false;
 
+#if (CONFIG_MMS_THREADLESS_STACK != 1)
     Semaphore_post(self->mmsMapping->isModelLockedMutex);
+#endif
 }
 
 #if (CONFIG_IEC61850_CONTROL_SERVICE == 1)
diff --git a/src/iec61850/server/mms_mapping/mms_mapping.c b/src/iec61850/server/mms_mapping/mms_mapping.c
index 096c90c7..14501840 100644
--- a/src/iec61850/server/mms_mapping/mms_mapping.c
+++ b/src/iec61850/server/mms_mapping/mms_mapping.c
@@ -3670,7 +3670,9 @@ MmsMapping_triggerReportObservers(MmsMapping* self, MmsValue* value, int flag)
 {
     LinkedList element = self->reportControls;
 
+#if (CONFIG_MMS_THREADLESS_STACK != 1)
     Semaphore_wait(self->isModelLockedMutex);
+#endif
 
     bool modelLocked = self->isModelLocked;
 
@@ -3708,7 +3710,9 @@ MmsMapping_triggerReportObservers(MmsMapping* self, MmsValue* value, int flag)
         Reporting_processReportEventsAfterUnlock(self);
     }
 
+#if (CONFIG_MMS_THREADLESS_STACK != 1)
     Semaphore_post(self->isModelLockedMutex);
+#endif
 }
 
 #endif /* (CONFIG_IEC61850_REPORT_SERVICE == 1) */
@@ -3729,13 +3733,17 @@ MmsMapping_triggerGooseObservers(MmsMapping* self, MmsValue* value)
             if (DataSet_isMemberValue(dataSet, value, NULL)) {
                 MmsGooseControlBlock_setStateChangePending(gcb);
 
+#if (CONFIG_MMS_THREADLESS_STACK != 1)
                 Semaphore_wait(self->isModelLockedMutex);
+#endif
 
                 if (self->isModelLocked == false) {
                     MmsGooseControlBlock_publishNewState(gcb);
                 }
 
+#if (CONFIG_MMS_THREADLESS_STACK != 1)
                 Semaphore_post(self->isModelLockedMutex);
+#endif
             }
         }
     }
diff --git a/src/iec61850/server/mms_mapping/reporting.c b/src/iec61850/server/mms_mapping/reporting.c
index ad60bef3..bada2732 100644
--- a/src/iec61850/server/mms_mapping/reporting.c
+++ b/src/iec61850/server/mms_mapping/reporting.c
@@ -3877,7 +3877,9 @@ processEventsForReport(ReportControl* rc, uint64_t currentTimeInMs)
 void
 Reporting_processReportEvents(MmsMapping* self, uint64_t currentTimeInMs)
 {
+#if (CONFIG_MMS_THREADLESS_STACK != 1)
     Semaphore_wait(self->isModelLockedMutex);
+#endif
 
     if (self->isModelLocked == false) {
 
@@ -3894,7 +3896,9 @@ Reporting_processReportEvents(MmsMapping* self, uint64_t currentTimeInMs)
         }
     }
 
+#if (CONFIG_MMS_THREADLESS_STACK != 1)
     Semaphore_post(self->isModelLockedMutex);
+#endif
 }
 
 /*