diff --git a/src/fat.c b/src/fat.c
index 7b92301..063243e 100644
--- a/src/fat.c
+++ b/src/fat.c
@@ -485,10 +485,10 @@ unsigned long update_free(DOS_FS *fs)
     }
 
     if (do_set) {
+	unsigned long le_free = CT_LE_L(free);
 	fs->free_clusters = free;
-	free = CT_LE_L(free);
 	fs_write(fs->fsinfo_start+offsetof(struct info_sector,free_clusters),
-		 sizeof(free),&free);
+		 sizeof(le_free), &le_free);
     }
 
     return free;