diff --git a/src/iec61850/server/impl/ied_server.c b/src/iec61850/server/impl/ied_server.c
index 1b804071..c6fdeffc 100644
--- a/src/iec61850/server/impl/ied_server.c
+++ b/src/iec61850/server/impl/ied_server.c
@@ -811,10 +811,10 @@ IedServer_stopThreadless(IedServer self)
 void
 IedServer_lockDataModel(IedServer self)
 {
-    Semaphore_wait(self->mmsMapping->isModelLockedMutex);
-
     MmsServer_lockModel(self->mmsServer);
 
+    Semaphore_wait(self->mmsMapping->isModelLockedMutex);
+
     self->mmsMapping->isModelLocked = true;
 
     Semaphore_post(self->mmsMapping->isModelLockedMutex);
@@ -833,10 +833,10 @@ IedServer_unlockDataModel(IedServer self)
 
     Semaphore_wait(self->mmsMapping->isModelLockedMutex);
 
-    self->mmsMapping->isModelLocked = false;
-
     MmsServer_unlockModel(self->mmsServer);
 
+    self->mmsMapping->isModelLocked = false;
+
     Semaphore_post(self->mmsMapping->isModelLockedMutex);
 }