diff --git a/src/calibre/ebooks/mobi/reader.py b/src/calibre/ebooks/mobi/reader.py
index 309023ede9..f80d15359c 100644
--- a/src/calibre/ebooks/mobi/reader.py
+++ b/src/calibre/ebooks/mobi/reader.py
@@ -475,8 +475,8 @@ class MobiReader(object):
         self.processed_html = self.processed_html.replace('\r\n', '\n')
         self.processed_html = self.processed_html.replace('> <', '>\n<')
         self.processed_html = self.processed_html.replace('<mbp: ', '<mbp:')
-        self.processed_html = re.sub(r'<?xml[^>]*>', '', self.processed_html)
-        # Swap inline and block level elements, and order block level elements according to priority 
+        self.processed_html = re.sub(r'<\?xml[^>]*>', '', self.processed_html)
+        # Swap inline and block level elements, and order block level elements according to priority
         # - lxml and beautifulsoup expect/assume a specific order based on xhtml spec
         self.processed_html = re.sub(r'(?i)(?P<styletags>(<(h\d+|i|b|u|em|small|big|strong|tt)>\s*){1,})(?P<para><p[^>]*>)', '\g<para>'+'\g<styletags>', self.processed_html)
         self.processed_html = re.sub(r'(?i)(?P<para></p[^>]*>)\s*(?P<styletags>(</(h\d+|i|b|u|em|small|big|strong|tt)>\s*){1,})', '\g<styletags>'+'\g<para>', self.processed_html)