diff --git a/scripts/generate_driver_wrappers.py b/scripts/generate_driver_wrappers.py
index 709f380..5223d45 100755
--- a/scripts/generate_driver_wrappers.py
+++ b/scripts/generate_driver_wrappers.py
@@ -163,7 +163,7 @@
     """
     Main with command line arguments.
     """
-    def_arg_project_root = build_tree.guess_mbedtls_root()
+    def_arg_project_root = build_tree.guess_project_root()
 
     parser = argparse.ArgumentParser()
     parser.add_argument('--project-root', default=def_arg_project_root,