diff --git a/wlauto/core/configuration.py b/wlauto/core/configuration.py
index 725119ff..66ea706b 100644
--- a/wlauto/core/configuration.py
+++ b/wlauto/core/configuration.py
@@ -676,7 +676,8 @@ class RunConfiguration(object):
     def _finalize_device_config(self):
         self._load_default_config_if_necessary(self.device)
         config = _merge_config_dicts(self._raw_config.get(self.device),
-                                     self._raw_config.get('device_config', {}))
+                                     self._raw_config.get('device_config', {}),
+                                     list_duplicates='all')
         self.device_config = config
 
     def _load_default_config_if_necessary(self, name):