diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
index 325f423..584aa55 100644
--- a/Python/pylifecycle.c
+++ b/Python/pylifecycle.c
@@ -928,7 +928,7 @@
     config._disable_importlib = !install_importlib;
     config.install_signal_handlers = install_sigs;
 
-    err = _PyCoreConfig_Read(&config);
+    err = _PyCoreConfig_Read(&config, &Py_IsolatedFlag, &Py_NoSiteFlag);
     if (_Py_INIT_FAILED(err)) {
         goto done;
     }