diff --git a/build_helper/build_helper_configs.py b/build_helper/build_helper_configs.py
index b2976de..39436c8 100644
--- a/build_helper/build_helper_configs.py
+++ b/build_helper/build_helper_configs.py
@@ -25,8 +25,7 @@
 config_AN521 = {"platform": ["AN521"],
                 "compiler": ["GNUARM"],
                 "config": ["ConfigRegression",
-                           "ConfigDefault",
-                           "ConfigCoreTest"],
+                           "ConfigDefault"],
                 "build": ["Debug"],
                 "with_mcuboot": [True],
                 # invalid configuations can be added as tuples of adjustable