diff --git a/ohmpi/hardware_components/mb_2023_0_X.py b/ohmpi/hardware_components/mb_2023_0_X.py
index a51d631ec64c44dcde5c6ce73d9c8bffd35d5b96..b1c187a8b5fda1e958b4fa706ed68b18ef088a74 100644
--- a/ohmpi/hardware_components/mb_2023_0_X.py
+++ b/ohmpi/hardware_components/mb_2023_0_X.py
@@ -108,8 +108,7 @@ def _gain_auto(channel):
 
 class Tx(TxAbstract):
     def __init__(self, **kwargs):
-        for key in kwargs.copy():
-            if key in SPECS['tx'].keys():
+        for key in SPECS['tx'].keys():
                 kwargs = enforce_specs(kwargs, SPECS['tx'], key)
         kwargs.update({'board_name': os.path.basename(__file__).rstrip('.py')})
         super().__init__(**kwargs)
@@ -254,9 +253,8 @@ class Tx(TxAbstract):
 
 class Rx(RxAbstract):
     def __init__(self, **kwargs):
-        for key in kwargs.copy():
-            if key in SPECS['rx'].keys():
-                kwargs = enforce_specs(kwargs, SPECS['rx'], key)
+        for key in SPECS['rx'].keys():
+            kwargs = enforce_specs(kwargs, SPECS['rx'], key)
         kwargs.update({'board_name': os.path.basename(__file__).rstrip('.py')})
         super().__init__(**kwargs)
         assert isinstance(self.connection, I2C)