From 75e6bd1452ad3b80ec8e4d49fdfaaddfbaa91ffa Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Wed, 30 Jun 2010 21:35:48 -0600
Subject: [PATCH] ...

---
 src/calibre/ebooks/metadata/opf2.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/calibre/ebooks/metadata/opf2.py b/src/calibre/ebooks/metadata/opf2.py
index 0bb0c570ed..36588471f2 100644
--- a/src/calibre/ebooks/metadata/opf2.py
+++ b/src/calibre/ebooks/metadata/opf2.py
@@ -1069,8 +1069,10 @@ class OPFCreator(MetaInformation):
             dc_attrs={'id':__appname__+'_id'}))
         if getattr(self, 'pubdate', None) is not None:
             a(DC_ELEM('date', self.pubdate.isoformat()))
-        a(DC_ELEM('language', self.language if self.language else
-            get_lang().replace('_', '-')))
+        lang = self.language
+        if not lang or lang.lower() == 'und':
+            lang = get_lang().replace('_', '-')
+        a(DC_ELEM('language', lang))
         if self.comments:
             a(DC_ELEM('description', self.comments))
         if self.publisher: