diff --git a/code/ryzom/server/src/ai_share/world_map.cpp b/code/ryzom/server/src/ai_share/world_map.cpp
index f468c1144..677e8cb97 100644
--- a/code/ryzom/server/src/ai_share/world_map.cpp
+++ b/code/ryzom/server/src/ai_share/world_map.cpp
@@ -372,7 +372,7 @@ uint16	CSingleLayerCell::_MaskMap[16];
 
 void CSingleLayerCell::serial(NLMISC::IStream& f)
 {
-	f.serialCheck((uint16)'SL');
+	f.serialCheck(NELID16("SL"));
 
 	uint i;
 	for (i=0; i<16; ++i)
@@ -403,7 +403,7 @@ void CSingleLayerCell::serial(NLMISC::IStream& f)
 
 void CMultiLayerCell::serial(NLMISC::IStream& f)
 {
-	f.serialCheck((uint16)'ML');
+	f.serialCheck(NELID16("ML"));
 
 	uint slot;