diff --git a/master/slave.c b/master/slave.c
index 59b6260d..83ae0d7f 100644
--- a/master/slave.c
+++ b/master/slave.c
@@ -1385,6 +1385,7 @@ void ecrt_slave_pdo_mapping_clear(
         return;
 
     ec_sync_clear_pdos(sync);
+    sync->alt_mapping = 1;
 }
 
 /*****************************************************************************/
diff --git a/master/sync.c b/master/sync.c
index 4bb56f0c..4a078e00 100644
--- a/master/sync.c
+++ b/master/sync.c
@@ -193,8 +193,6 @@ void ec_sync_clear_pdos(
         ec_pdo_clear(pdo);
         kfree(pdo);
     }
-
-    sync->alt_mapping = 1;
 }
 
 /*****************************************************************************/