diff --git a/webservice/update_config.py b/webservice/update_config.py
index be00c979cf91ee7f7d8b20af30cf276b34b9b343..0d3cf58f1f45be6e51be83eaf31b6046aac43805 100644
--- a/webservice/update_config.py
+++ b/webservice/update_config.py
@@ -64,12 +64,14 @@ bool_keys = []
 
 # Avoid erros when karabo_id not yet given through the command line.
 if karabo_id is not None:
+    # adding "no" bools to available options
     for det, val in available_options[karabo_id][0].items():
         if val['typ'] == bool:
             bool_keys.append(det)
 
     for b in bool_keys:
-        available_options[karabo_id][0]['no-{}'.format(b)] = {'typ': bool}
+        available_options[karabo_id][0]['no-{}'.format(det)] = {'typ': bool}
+
     for exposed_options in available_options[karabo_id]:
         for option, info in exposed_options.items():
             metavar = None