diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,3 +1,9 @@
+## 2.0.1
+
+* Bug fix for defaultReadN.
+* Providing allocSimpleConfig and freeSimpleConfig.
+* Deprecating makeSimpleConfig.
+
 ## 2.0.0
 
 * Providing Network.HTTP.Server.
diff --git a/Network/HTTP2/Server.hs b/Network/HTTP2/Server.hs
--- a/Network/HTTP2/Server.hs
+++ b/Network/HTTP2/Server.hs
@@ -17,37 +17,46 @@
 -- > import Network.Socket
 -- >
 -- > main :: IO ()
--- > main = withSocketsDo $ do
--- >     addr <- resolve "80"
--- >     E.bracket (open addr) close loop
+-- > main = runTCPServer "80" $ \s _peer -> runHTTP2Server s
 -- >   where
--- >     server _req _ctl sendResponse = sendResponse response []
+-- >     runHTTP2Server s = E.bracket (allocSimpleConfig s 4096)
+-- >                                  (\config -> run config server)
+-- >                                  freeSimpleConfig
+-- >     server _req _aux sendResponse = sendResponse response []
 -- >       where
--- >         response = responseBuilder ok200 [("Content-Type", "text/plain")] (byteString "Hello, world!\n")
--- >     loop sock = forever $ do
--- >         (s, _peer) <- accept sock
--- >         (config, cleanup) <- makeSimpleConfig s 4096
--- >         void $ forkFinally (run config server) (\_ -> close s >> cleanup)
--- >     resolve port = do
+-- >         response = responseBuilder ok200 header body
+-- >         header = [("Content-Type", "text/plain")]
+-- >         body = byteString "Hello, world!\n"
+-- >
+-- > runTCPServer :: String -> (Socket -> SockAddr -> IO a) -> IO a
+-- > runTCPServer port server = withSocketsDo $ do
+-- >     addr <- resolve
+-- >     E.bracket (open addr) close loop
+-- >   where
+-- >     resolve = do
 -- >         let hints = defaultHints {
 -- >                 addrFlags = [AI_PASSIVE]
 -- >               , addrSocketType = Stream
 -- >               }
--- >         addr:_ <- getAddrInfo (Just hints) Nothing (Just port)
--- >         return addr
+-- >         head <$> getAddrInfo (Just hints) Nothing (Just port)
 -- >     open addr = do
 -- >         sock <- socket (addrFamily addr) (addrSocketType addr) (addrProtocol addr)
 -- >         setSocketOption sock ReuseAddr 1
 -- >         withFdSocket sock $ setCloseOnExecIfNeeded
--- >         bind sock (addrAddress addr)
--- >         listen sock 10
+-- >         bind sock $ addrAddress addr
+-- >         listen sock 1024
 -- >         return sock
+-- >     loop sock = forever $ do
+-- >         (conn, peer) <- accept sock
+-- >         void $ forkFinally (server conn peer) (\_ -> close conn)
 
 module Network.HTTP2.Server (
   -- * Runner
     run
   -- * Runner arguments
   , Config(..)
+  , allocSimpleConfig
+  , freeSimpleConfig
   , makeSimpleConfig
   -- * HTTP/2 server
   , Server
@@ -101,7 +110,7 @@
 import Imports
 import Network.HPACK
 import Network.HTTP2.Server.API
-import Network.HTTP2.Server.Config (makeSimpleConfig)
+import Network.HTTP2.Server.Config
 import Network.HTTP2.Server.File (defaultPositionReadMaker)
 import Network.HTTP2.Server.ReadN (defaultReadN)
 import Network.HTTP2.Server.Run (run)
diff --git a/Network/HTTP2/Server/Config.hs b/Network/HTTP2/Server/Config.hs
--- a/Network/HTTP2/Server/Config.hs
+++ b/Network/HTTP2/Server/Config.hs
@@ -10,11 +10,19 @@
 import Network.HTTP2.Server.File
 import Network.HTTP2.Server.ReadN
 
+{-# DEPRECATED makeSimpleConfig "Use allocSimpleConfig instead" #-}
 -- | Making configuration whose IO is not efficient.
 --   A write buffer is allocated internally.
 --   That should be deallocated by the returned action.
 makeSimpleConfig :: Socket -> BufferSize -> IO (Config, IO ())
 makeSimpleConfig s bufsiz = do
+    config <- allocSimpleConfig s bufsiz
+    return (config, freeSimpleConfig config)
+
+-- | Making simple configuration whose IO is not efficient.
+--   A write buffer is allocated internally.
+allocSimpleConfig :: Socket -> BufferSize -> IO Config
+allocSimpleConfig s bufsiz = do
     buf <- mallocBytes bufsiz
     ref <- newIORef Nothing
     let config = Config {
@@ -24,4 +32,8 @@
           , confReadN = defaultReadN s ref
           , confPositionReadMaker = defaultPositionReadMaker
           }
-    return (config, free buf)
+    return config
+
+-- | Deallocating the resource of the simple configuration.
+freeSimpleConfig :: Config -> IO ()
+freeSimpleConfig conf = free $ confWriteBuffer conf
diff --git a/Network/HTTP2/Server/ReadN.hs b/Network/HTTP2/Server/ReadN.hs
--- a/Network/HTTP2/Server/ReadN.hs
+++ b/Network/HTTP2/Server/ReadN.hs
@@ -7,13 +7,16 @@
 
 -- | Naive implementation for readN.
 defaultReadN :: Socket -> IORef (Maybe B.ByteString) -> Int -> IO B.ByteString
+defaultReadN _ _   0 = return B.empty
 defaultReadN s ref n = do
     mbs <- readIORef ref
     writeIORef ref Nothing
     case mbs of
       Nothing -> do
           bs <- N.recv s n
-          if B.length bs == n then
+          if B.null bs then
+              return B.empty
+          else if B.length bs == n then
               return bs
             else
               loop bs
@@ -28,8 +31,11 @@
     loop bs = do
         let n' = n - B.length bs
         bs1 <- N.recv s n'
-        let bs2 = bs `B.append` bs1
-        if B.length bs2 == n then
-            return bs2
-          else
-            loop bs2
+        if B.null bs1 then
+            return B.empty
+          else do
+            let bs2 = bs `B.append` bs1
+            if B.length bs2 == n then
+                return bs2
+              else
+                loop bs2
diff --git a/http2.cabal b/http2.cabal
--- a/http2.cabal
+++ b/http2.cabal
@@ -1,5 +1,5 @@
 Name:                   http2
-Version:                2.0.0
+Version:                2.0.1
 Author:                 Kazu Yamamoto <kazu@iij.ad.jp>
 Maintainer:             Kazu Yamamoto <kazu@iij.ad.jp>
 License:                BSD3
@@ -102,7 +102,7 @@
                       , containers >= 0.5
                       , http-types
                       , network
-                      , network-byte-order
+                      , network-byte-order >= 0.1.1
                       , psqueues
                       , stm
                       , time-manager