diff --git a/src/calibre/ebooks/oeb/reader.py b/src/calibre/ebooks/oeb/reader.py
index e0bcc4147c..57fa974bb3 100644
--- a/src/calibre/ebooks/oeb/reader.py
+++ b/src/calibre/ebooks/oeb/reader.py
@@ -338,8 +338,15 @@ class OEBReader(object):
             href = elem.get('href')
             path = urlnormalize(urldefrag(href)[0])
             if path not in manifest.hrefs:
-                self.logger.warn(u'Guide reference %r not found' % href)
-                continue
+                corrected_href = None
+                for href in manifest.hrefs:
+                    if href.lower() == path.lower():
+                        corrected_href = href
+                        break
+                if corrected_href is None:
+                    self.logger.warn(u'Guide reference %r not found' % href)
+                    continue
+                href = corrected_href
             guide.add(elem.get('type'), elem.get('title'), href)
 
     def _find_ncx(self, opf):
diff --git a/src/calibre/ebooks/oeb/transforms/guide.py b/src/calibre/ebooks/oeb/transforms/guide.py
index 870e1b5f75..6bea98f073 100644
--- a/src/calibre/ebooks/oeb/transforms/guide.py
+++ b/src/calibre/ebooks/oeb/transforms/guide.py
@@ -15,10 +15,10 @@ class Clean(object):
 
         if 'cover' not in self.oeb.guide:
             covers = []
-            for x in ('other.ms-coverimage-standard',
+            for x in ('other.ms-coverimage-standard', 'coverimagestandard',
                     'other.ms-titleimage-standard', 'other.ms-titleimage',
                     'other.ms-coverimage', 'other.ms-thumbimage-standard',
-                    'other.ms-thumbimage'):
+                    'other.ms-thumbimage', 'thumbimagestandard'):
                 if x in self.oeb.guide:
                     href = self.oeb.guide[x].href
                     item = self.oeb.manifest.hrefs[href]