diff --git a/src/calibre/devices/kindle/apnx.py b/src/calibre/devices/kindle/apnx.py
index 9f378cada1..223fa90ea4 100644
--- a/src/calibre/devices/kindle/apnx.py
+++ b/src/calibre/devices/kindle/apnx.py
@@ -280,7 +280,7 @@ def get_pages_pagebreak_tag(self, mobi_file_path):
         mr.extract_text()
 
         html = mr.mobi_html.lower()
-        for m in re.finditer('<\s*(mbp:)?pagebreak[^>]*>', html):
+        for m in re.finditer('<[^>]*pagebreak[^>]*>', html):
             pages.append(m.end())
 
         return pages