diff --git a/src/calibre/ebooks/oeb/polish/check/links.py b/src/calibre/ebooks/oeb/polish/check/links.py
index a8e7954488..8f6e9bf5e1 100644
--- a/src/calibre/ebooks/oeb/polish/check/links.py
+++ b/src/calibre/ebooks/oeb/polish/check/links.py
@@ -102,6 +102,8 @@ def check_mimetypes(container):
     for name, mt in container.mime_map.iteritems():
         gt = container.guess_type(name)
         if mt != gt:
+            if mt == 'application/oebps-page-map+xml' and name.lower().endswith('.xml'):
+                continue
             a(MimetypeMismatch(container, name, mt, gt))
     return errors
 
diff --git a/src/calibre/gui2/tweak_book/editor/__init__.py b/src/calibre/gui2/tweak_book/editor/__init__.py
index 25cee316af..94215621d4 100644
--- a/src/calibre/gui2/tweak_book/editor/__init__.py
+++ b/src/calibre/gui2/tweak_book/editor/__init__.py
@@ -16,7 +16,7 @@ def syntax_from_mime(name, mime):
         return 'html'
     if mime in OEB_STYLES:
         return 'css'
-    if mime in {guess_type('a.opf'), guess_type('a.ncx'), guess_type('a.xml')}:
+    if mime in {guess_type('a.opf'), guess_type('a.ncx'), guess_type('a.xml'), 'application/oebps-page-map+xml'}:
         return 'xml'
     if mime.startswith('text/'):
         return 'text'