diff --git a/src/pyedb/configuration/cfg_data.py b/src/pyedb/configuration/cfg_data.py
index 4f3045b787..8e5ef56a2d 100644
--- a/src/pyedb/configuration/cfg_data.py
+++ b/src/pyedb/configuration/cfg_data.py
@@ -56,7 +56,9 @@ def __init__(self, pedb, **kwargs):
         self.setups = [CfgSetup(self)]
         if kwargs.get("setups", None):
             self.setups = [CfgSetup(self, setup) for setup in kwargs.get("setups", [])]
-        self.stackup = CfgLayerStackup(self, kwargs.get("materials", {}), kwargs.get("layers", {}))
+        self.stackup = CfgLayerStackup(
+            self, kwargs.get("stackup", {}).get("materials", {}), kwargs.get("stackup", {}).get("layers", {})
+        )
         self.s_parameters = [
             CfgSParameterModel(self, self.general.s_parameter_library, sparam_model)
             for sparam_model in kwargs.get("s_parameters", [])
diff --git a/src/pyedb/configuration/cfg_stackup.py b/src/pyedb/configuration/cfg_stackup.py
index 5a4c97e84c..a39af8e8e1 100644
--- a/src/pyedb/configuration/cfg_stackup.py
+++ b/src/pyedb/configuration/cfg_stackup.py
@@ -39,9 +39,9 @@ def __init__(self, pdata, materials=None, layers=None):
         self.materials = []
         self.layers = []
         if self._materials_dict:
-            self.materials = [Material(self._pedb, material_dict) for material_dict in self._materials_dict.items()]
+            self.materials = [Material(self._pedb, material_dict) for material_dict in self._materials_dict]
         if self._layers_dict:
-            self.layers = [Layer(self._pedb, layer_dict) for layer_dict in self._layers_dict.items()]
+            self.layers = [Layer(self._pedb, layer_dict) for layer_dict in self._layers_dict]
 
     def apply(self):
         for material in self.materials: