diff --git a/src/calibre/devices/android/driver.py b/src/calibre/devices/android/driver.py
index d478f47cea..8f5395b514 100644
--- a/src/calibre/devices/android/driver.py
+++ b/src/calibre/devices/android/driver.py
@@ -167,7 +167,7 @@ class ANDROID(USBMS):
             'MB525', 'ANDROID2.3', 'SGH-I997', 'GT-I5800_CARD', 'MB612',
             'GT-S5830_CARD', 'GT-S5570_CARD', 'MB870', 'MID7015A',
             'ALPANDIGITAL', 'ANDROID_MID', 'VTAB1008', 'EMX51_BBG_ANDROI',
-            'UMS', '.K080', 'P990', 'LTE', 'MB853']
+            'UMS', '.K080', 'P990', 'LTE', 'MB853', 'GT-S5660_CARD']
     WINDOWS_CARD_A_MEM = ['ANDROID_PHONE', 'GT-I9000_CARD', 'SGH-I897',
             'FILE-STOR_GADGET', 'SGH-T959', 'SAMSUNG_ANDROID', 'GT-P1000_CARD',
             'A70S', 'A101IT', '7', 'INCREDIBLE', 'A7EB', 'SGH-T849_CARD',
diff --git a/src/calibre/ebooks/oeb/stylizer.py b/src/calibre/ebooks/oeb/stylizer.py
index adef0f1bfb..20be750925 100644
--- a/src/calibre/ebooks/oeb/stylizer.py
+++ b/src/calibre/ebooks/oeb/stylizer.py
@@ -539,7 +539,8 @@ class Style(object):
         'Return value in pts'
         if base is None:
             base = self.width
-        font = font or self.fontSize
+        if not font and font != 0:
+            font = self.fontSize
         return unit_convert(value, base, font, self._profile.dpi)
 
     def pt_to_px(self, value):
diff --git a/src/calibre/ebooks/oeb/transforms/flatcss.py b/src/calibre/ebooks/oeb/transforms/flatcss.py
index ba90a31632..489498d90c 100644
--- a/src/calibre/ebooks/oeb/transforms/flatcss.py
+++ b/src/calibre/ebooks/oeb/transforms/flatcss.py
@@ -283,7 +283,10 @@ class CSSFlattener(object):
                 psize = fsize
             elif 'font-size' in cssdict or tag == 'body':
                 fsize = self.fmap[font_size]
-                cssdict['font-size'] = "%0.5fem" % (fsize / psize)
+                try:
+                    cssdict['font-size'] = "%0.5fem" % (fsize / psize)
+                except ZeroDivisionError:
+                    cssdict['font-size'] = '%.1fpt'%fsize
                 psize = fsize
 
         try: