diff --git a/Codec/Binary/UTF8/Generic.hs b/Codec/Binary/UTF8/Generic.hs
--- a/Codec/Binary/UTF8/Generic.hs
+++ b/Codec/Binary/UTF8/Generic.hs
@@ -32,6 +32,10 @@
 
 import Codec.Binary.UTF8.String(encode)
 
+#ifdef BYTESTRING_IN_BASE
+import Data.ByteString.Base (unsafeHead, unsafeTail)
+#endif
+
 class (Num s, Ord s) => UTF8Bytes b s | b -> s where
   bsplit        :: s -> b -> (b,b)
   bdrop         :: s -> b -> b
@@ -45,7 +49,7 @@
 instance UTF8Bytes B.ByteString Int where
   bsplit        = B.splitAt
   bdrop         = B.drop
-  buncons       = B.uncons
+  buncons       = unconsB
   elemIndex     = B.elemIndex
   empty         = B.empty
   null          = B.null
@@ -55,7 +59,7 @@
 instance UTF8Bytes L.ByteString Int64 where
   bsplit        = L.splitAt
   bdrop         = L.drop
-  buncons       = L.uncons
+  buncons       = unconsL
   elemIndex     = L.elemIndex
   empty         = L.empty
   null          = L.null
@@ -267,3 +271,20 @@
                         in xs : lines' ys
               Nothing -> [bs]
 
+-----------
+-- Compatibility functions for base-2
+
+unconsB :: B.ByteString -> Maybe (Word8,B.ByteString)
+unconsL :: L.ByteString -> Maybe (Word8,L.ByteString)
+
+#ifdef BYTESTRING_IN_BASE
+unconsB bs | B.null bs = Nothing
+           | otherwise = Just (unsafeHead bs, unsafeTail bs)
+
+unconsL bs = case L.toChunks bs of
+    (x:xs) | not (B.null x)     -> Just (unsafeHead x, L.fromChunks (unsafeTail x:xs))
+    _                           -> Nothing
+#else
+unconsB = B.uncons
+unconsL = L.uncons
+#endif
diff --git a/Data/ByteString/Lazy/UTF8.hs b/Data/ByteString/Lazy/UTF8.hs
--- a/Data/ByteString/Lazy/UTF8.hs
+++ b/Data/ByteString/Lazy/UTF8.hs
@@ -28,6 +28,7 @@
 import Prelude hiding (take,drop,splitAt,span,break,foldr,foldl,length,lines)
 
 import Codec.Binary.UTF8.String(encode)
+import Codec.Binary.UTF8.Generic (buncons)
 
 -- | Converts a Haskell string into a UTF8 encoded bytestring.
 fromString :: String -> B.ByteString
@@ -51,7 +52,7 @@
 -- XXX: Should we combine sequences of errors into a single replacement
 -- character?
 decode :: B.ByteString -> Maybe (Char,Int64)
-decode bs = do (c,cs) <- B.uncons bs
+decode bs = do (c,cs) <- buncons bs
                return (choose (fromEnum c) cs)
   where
   choose :: Int -> B.ByteString -> (Char, Int64)
@@ -75,7 +76,7 @@
 
   {-# INLINE get_follower #-}
   get_follower :: Int -> B.ByteString -> Maybe (Int, B.ByteString)
-  get_follower acc cs = do (x,xs) <- B.uncons cs
+  get_follower acc cs = do (x,xs) <- buncons cs
                            acc1 <- follower acc x
                            return (acc1,xs)
 
diff --git a/Data/ByteString/UTF8.hs b/Data/ByteString/UTF8.hs
--- a/Data/ByteString/UTF8.hs
+++ b/Data/ByteString/UTF8.hs
@@ -27,6 +27,7 @@
 import Prelude hiding (take,drop,splitAt,span,break,foldr,foldl,length,lines)
 
 import Codec.Binary.UTF8.String(encode)
+import Codec.Binary.UTF8.Generic (buncons)
 
 -- | Converts a Haskell string into a UTF8 encoded bytestring.
 fromString :: String -> B.ByteString
@@ -50,7 +51,7 @@
 -- XXX: Should we combine sequences of errors into a single replacement
 -- character?
 decode :: B.ByteString -> Maybe (Char,Int)
-decode bs = do (c,cs) <- B.uncons bs
+decode bs = do (c,cs) <- buncons bs
                return (choose (fromEnum c) cs)
   where
   choose :: Int -> B.ByteString -> (Char, Int)
@@ -74,7 +75,7 @@
 
   {-# INLINE get_follower #-}
   get_follower :: Int -> B.ByteString -> Maybe (Int, B.ByteString)
-  get_follower acc cs = do (x,xs) <- B.uncons cs
+  get_follower acc cs = do (x,xs) <- buncons cs
                            acc1 <- follower acc x
                            return (acc1,xs)
 
diff --git a/System/IO/UTF8.hs b/System/IO/UTF8.hs
--- a/System/IO/UTF8.hs
+++ b/System/IO/UTF8.hs
@@ -36,6 +36,7 @@
                 Show(..))
 import System.IO (Handle, IO, FilePath, IOMode(AppendMode, ReadMode, WriteMode))
 import qualified System.IO as IO
+import Control.Exception (bracket)
 
 import Codec.Binary.UTF8.String (encode, decode)
 
@@ -83,7 +84,7 @@
 openBinaryFile n m = IO.openBinaryFile (encodeString n) m
 
 withBinaryFile :: FilePath -> IOMode -> (Handle -> IO a) -> IO a
-withBinaryFile n m f = IO.withBinaryFile (encodeString n) m f
+withBinaryFile n m f = bracket (openBinaryFile n m) IO.hClose f
 
 -- | The 'readFile' function reads a file and
 -- returns the contents of the file as a UTF8 string.
diff --git a/utf8-string.cabal b/utf8-string.cabal
--- a/utf8-string.cabal
+++ b/utf8-string.cabal
@@ -1,5 +1,5 @@
 Name:               utf8-string
-Version:            0.3.3
+Version:            0.3.4
 Author:             Eric Mertens
 Maintainer:         emertens@galois.com
 License:            BSD3
@@ -21,9 +21,11 @@
 
   if flag(bytestring-in-base)
     build-depends: base >= 2.0 && < 2.2
+    cpp-options: -DBYTESTRING_IN_BASE
   else
     build-depends: base < 2.0 || >= 3, bytestring >= 0.9
 
+  Extensions:         CPP
   Exposed-modules:    Codec.Binary.UTF8.String
                       Codec.Binary.UTF8.Generic
                       System.IO.UTF8