diff --git a/fints/client.py b/fints/client.py
index 42584db..1fbc42d 100644
--- a/fints/client.py
+++ b/fints/client.py
@@ -1220,10 +1220,10 @@ def _get_tan_segment(self, orig_seg, tan_process, tan_seg=None):
             raise NotImplementedError("TAN-Process 1 not implemented")
 
         if tan_process in ('1', '3', '4') and self.is_tan_media_required():
-            if self.selected_tan_medium:
+            if self.selected_tan_medium is not None:
                 seg.tan_medium_name = self.selected_tan_medium
             else:
-                seg.tan_medium_name = 'DUMMY'
+                seg.tan_medium_name = ''
 
         if tan_process == '4' and tan_mechanism.VERSION >= 6:
             seg.segment_type = orig_seg.header.type
diff --git a/fints/dialog.py b/fints/dialog.py
index e115d69..0c97daf 100644
--- a/fints/dialog.py
+++ b/fints/dialog.py
@@ -86,12 +86,13 @@ def init(self, *extra_segments):
 
                 if tan_seg:
                     for resp in retval.responses(tan_seg):
-                        if resp.code == '0030':
+                        if resp.code in ('0030', '3955'):
                             self.client.init_tan_response = NeedTANResponse(
                                 None,
                                 retval.find_segment_first('HITAN'),
                                 '_continue_dialog_initialization',
-                                self.client.is_challenge_structured()
+                                self.client.is_challenge_structured(),
+                                resp.code == '3955',
                             )
                 self.need_init = False
                 return retval
diff --git a/fints/utils.py b/fints/utils.py
index 5e009a6..130f5b6 100644
--- a/fints/utils.py
+++ b/fints/utils.py
@@ -295,7 +295,7 @@ def minimal_interactive_cli_bootstrap(client):
             choice = input("Choice: ").strip()
             client.set_tan_mechanism(mechanisms[int(choice)][0])
 
-    if client.is_tan_media_required() and not client.selected_tan_medium:
+    if client.selected_tan_medium is None and client.is_tan_media_required():
         print("We need the name of the TAN medium, let's fetch them from the bank")
         m = client.get_tan_media()
         if len(m[1]) == 1: