diff --git a/src/calibre/ebooks/mobi/writer8/main.py b/src/calibre/ebooks/mobi/writer8/main.py
index acba9be454..f6847fdca0 100644
--- a/src/calibre/ebooks/mobi/writer8/main.py
+++ b/src/calibre/ebooks/mobi/writer8/main.py
@@ -314,7 +314,7 @@ class KF8Writer(object):
             return
 
         # Flatten the ToC into a depth first list
-        fl = toc.iter() if is_periodical else toc.iterdescendants()
+        fl = toc.iterdescendants()
         for i, item in enumerate(fl):
             entry = {'id': id(item), 'index': i, 'href':item.href or '',
                     'label':(item.title or _('Unknown')),