diff --git a/ohmpi/hardware_components/mb_2023_0_X.py b/ohmpi/hardware_components/mb_2023_0_X.py
index 8f892aec749a0b8eda61347c9c6efd6d4ba08997..faa6f94c9f315bb612ea27f5d24fe84f46a7b75c 100644
--- a/ohmpi/hardware_components/mb_2023_0_X.py
+++ b/ohmpi/hardware_components/mb_2023_0_X.py
@@ -108,7 +108,7 @@ def _gain_auto(channel):
 
 class Tx(TxAbstract):
     def __init__(self, **kwargs):
-        for key in kwargs.keys():
+        for key in kwargs.copy():
             if key in SPECS['tx'].keys():
                 kwargs = enforce_specs(kwargs, SPECS['tx'], key)
         kwargs.update({'board_name': os.path.basename(__file__).rstrip('.py')})
@@ -253,7 +253,7 @@ class Tx(TxAbstract):
 
 class Rx(RxAbstract):
     def __init__(self, **kwargs):
-        for key in kwargs.keys():
+        for key in kwargs.copy():
             if key in SPECS['rx'].keys():
                 kwargs = enforce_specs(kwargs, SPECS['rx'], key)
         kwargs.update({'board_name': os.path.basename(__file__).rstrip('.py')})