diff --git a/src/calibre/devices/prs500/books.py b/src/calibre/devices/prs500/books.py
index db25e7d14c..6c57920487 100644
--- a/src/calibre/devices/prs500/books.py
+++ b/src/calibre/devices/prs500/books.py
@@ -258,7 +258,7 @@ class BookList(_BookList):
         if book is not None:
             self.remove_book(name)
         node = self.document.createElement(self.prefix + "text")
-        mime = MIME_MAP[name[name.rfind(".")+1:]]
+        mime = MIME_MAP[name[name.rfind(".")+1:].lower()]
         cid = self.max_id()+1
         sourceid = str(self[0].sourceid) if len(self) else "1"
         attrs = {
diff --git a/src/calibre/devices/prs505/books.py b/src/calibre/devices/prs505/books.py
index a917aa00ae..c97d430d4b 100644
--- a/src/calibre/devices/prs505/books.py
+++ b/src/calibre/devices/prs505/books.py
@@ -184,7 +184,7 @@ class BookList(_BookList):
             self.remove_book(name)
                 
         node = self.document.createElement(self.prefix + "text")
-        mime = MIME_MAP[name.rpartition('.')[-1]]
+        mime = MIME_MAP[name.rpartition('.')[-1].lower()]
         cid = self.max_id()+1
         sourceid = str(self[0].sourceid) if len(self) else "1"
         attrs = {
diff --git a/src/calibre/gui2/library.py b/src/calibre/gui2/library.py
index 755eef6a1e..ba8101521c 100644
--- a/src/calibre/gui2/library.py
+++ b/src/calibre/gui2/library.py
@@ -128,7 +128,7 @@ class BooksModel(QAbstractTableModel):
         for row in rows:
             if self.cover_cache:
                 id = self.db.id(row)
-                self.cover_cache.refresh(id)
+                self.cover_cache.refresh([id])
             if row == current_row:
                 self.emit(SIGNAL('new_bookdisplay_data(PyQt_PyObject)'),
                           self.get_book_display_info(row))
diff --git a/src/calibre/library/database2.py b/src/calibre/library/database2.py
index 7d287ebfcb..684c308a2d 100644
--- a/src/calibre/library/database2.py
+++ b/src/calibre/library/database2.py
@@ -139,7 +139,7 @@ class CoverCache(QThread):
         self.cache_lock.unlock()
         self.load_queue_lock.lockForWrite()
         for id in ids:
-            self.load_queue.append_left(id)
+            self.load_queue.appendleft(id)
         self.load_queue_lock.unlock()
     
 class Concatenate(object):
diff --git a/src/calibre/utils/filenames.py b/src/calibre/utils/filenames.py
index de966b14c9..bcd30068e8 100644
--- a/src/calibre/utils/filenames.py
+++ b/src/calibre/utils/filenames.py
@@ -73,6 +73,10 @@ MAP = {
         u"ь" : u"'",
         }  #: Translation table
 
+for c in string.whitespace:
+    MAP[c] = ' '
+PAT = re.compile('['+u''.join(MAP.keys())+']')
+
 def ascii_filename(orig):
     orig =  PAT.sub(lambda m:MAP[m.group()], orig)
     buf = []