diff --git a/src/calibre/ebooks/oeb/transforms/split.py b/src/calibre/ebooks/oeb/transforms/split.py
index 60d036a369..512215e6d9 100644
--- a/src/calibre/ebooks/oeb/transforms/split.py
+++ b/src/calibre/ebooks/oeb/transforms/split.py
@@ -138,7 +138,7 @@ class Split(object):
             page_breaks_.append((xp, x.get('pb_before', '0') == '1'))
             page_break_ids.append(id)
 
-        for elem in item.data.iter():
+        for elem in item.data.iter(etree.Element):
             elem.attrib.pop('pb_order', False)
             elem.attrib.pop('pb_before', False)