diff --git a/imagine/magnetic_fields/magnetic_field/magnetic_field_factory.py b/imagine/magnetic_fields/magnetic_field/magnetic_field_factory.py
index 4e36091097e0fc57e9ee15508d5778069a06e9cc..cc7c098c188035867d4d1a347e6c4692de2ea1f5 100644
--- a/imagine/magnetic_fields/magnetic_field/magnetic_field_factory.py
+++ b/imagine/magnetic_fields/magnetic_field/magnetic_field_factory.py
@@ -108,8 +108,8 @@ class MagneticFieldFactory(Loggable, object):
         for k, v in new_mapping.items():
             if k in self._variable_to_parameter_mappings:
                 key = str(k)
-                value = [np.float(v[1]), np.float(v[2]), np.float(v[3])]
-                self._variable_to_parameter_mappings.update((key, value))
+                value = [np.float(v[0]), np.float(v[1])]
+                self._variable_to_parameter_mappings.update({key: value})
                 self.logger.debug("Updated variable_to_parameter_mapping %s "
                                   "to %s" % (key, str(value)))
 
diff --git a/imagine/pipeline.py b/imagine/pipeline.py
index 3aca58ca50b486291e997d1c2b476df8a9b75be1..a2aecb454de8335148e4f6a71c16e77560c681b1 100644
--- a/imagine/pipeline.py
+++ b/imagine/pipeline.py
@@ -152,7 +152,7 @@ class Pipeline(Loggable, object):
         # the worst possible likelihood value
         if np.any(cube_content > 1.) or np.any(cube_content < 0.):
             self.logger.info('Cube %s requested. Returned most negative '
-                             'possible number.')
+                             'possible number.' % cube_content)
             return np.nan_to_num(-np.inf)
 
         if rank != 0: