diff --git a/Data/Text/Encoding/Locale.hs b/Data/Text/Encoding/Locale.hs
--- a/Data/Text/Encoding/Locale.hs
+++ b/Data/Text/Encoding/Locale.hs
@@ -10,7 +10,7 @@
 -- This module provides functions to encode and decode 'Data.Text.Text' to/from
 -- 'Data.ByteString.ByteString' using 'System.IO.TextEncoding'
 --
--- For performance, Text\'s native decode\* functions are used if the conditions
+-- For performance, Text\'s native encoding functions are used if the conditions
 -- are right (LF NewlineMode and UTF encoding).
 {-# LANGUAGE CPP #-}
 #ifdef TRUSTWORTHY
@@ -37,7 +37,6 @@
 
 import Data.ByteString.Handle
 
-import qualified Data.List as L
 import Data.Maybe
 
 handleDecoder :: Maybe TextEncoding -> Maybe NewlineMode -> B.ByteString -> IO T.Text
@@ -61,10 +60,10 @@
       -- decode* functions won't convert line ends
       then do
         enc <- maybe getLocale' return menc
-        case L.stripPrefix "UTF-" (show enc) of
-          Just s ->
+        case show enc of
+          'U':'T':'F':'-':s ->
             case s of
-              "8" -> return (TE.decodeUtf8 bs)
+              '8':[] -> return (TE.decodeUtf8 bs)
               ('1':'6':x:'E':_)
                   | 'L' == x -> return (TE.decodeUtf16LE bs)
                   | 'B' == x -> return (TE.decodeUtf16BE bs)
@@ -85,10 +84,10 @@
       -- encode* functions won't convert line ends
       then do
         enc <- maybe getLocale' return menc
-        case L.stripPrefix "UTF-" (show enc) of
-          Just s ->
+        case show enc of
+          'U':'T':'F':'-':s ->
             case s of
-              "8" -> return (TE.encodeUtf8 bs)
+              '8':[] -> return (TE.encodeUtf8 bs)
               ('1':'6':x:'E':_)
                   | 'L' == x -> return (TE.encodeUtf16LE bs)
                   | 'B' == x -> return (TE.encodeUtf16BE bs)
diff --git a/Data/Text/Lazy/Encoding/Locale.hs b/Data/Text/Lazy/Encoding/Locale.hs
--- a/Data/Text/Lazy/Encoding/Locale.hs
+++ b/Data/Text/Lazy/Encoding/Locale.hs
@@ -1,5 +1,5 @@
 -- |
--- module: Data.Text.Encoding.Locale
+-- module: Data.Text.Lazy.Encoding.Locale
 -- copyright: © kudah 2013
 -- license: BSD3
 --
@@ -10,7 +10,7 @@
 -- This module provides functions to encode and decode 'Data.Text.Lazy.Text'
 -- to/from 'Data.ByteString.Lazy.ByteString' using 'System.IO.TextEncoding'
 --
--- For performance, Text\'s native decode\* functions are used if the conditions
+-- For performance, Text\'s native encoding functions are used if the conditions
 -- are right (LF NewlineMode and UTF encoding).
 {-# LANGUAGE CPP #-}
 #ifdef TRUSTWORTHY
@@ -39,7 +39,6 @@
 
 import Data.ByteString.Handle
 
-import qualified Data.List as L
 import Data.Maybe
 
 handleDecoder :: Maybe TextEncoding -> Maybe NewlineMode -> L.ByteString -> IO TL.Text
@@ -63,10 +62,10 @@
       -- decode* functions won't convert line ends
       then do
         enc <- maybe getLocale' return menc
-        case L.stripPrefix "UTF-" (show enc) of
-          Just s ->
+        case show enc of
+          'U':'T':'F':'-':s ->
             case s of
-              "8" -> return (TLE.decodeUtf8 bs)
+              '8':[] -> return (TLE.decodeUtf8 bs)
               ('1':'6':x:'E':_)
                   | 'L' == x -> return (TLE.decodeUtf16LE bs)
                   | 'B' == x -> return (TLE.decodeUtf16BE bs)
@@ -87,10 +86,10 @@
       -- encode* functions won't convert line ends
       then do
         enc <- maybe getLocale' return menc
-        case L.stripPrefix "UTF-" (show enc) of
-          Just s ->
+        case show enc of
+          'U':'T':'F':'-':s ->
             case s of
-              "8" -> return (TLE.encodeUtf8 bs)
+              '8':[] -> return (TLE.encodeUtf8 bs)
               ('1':'6':x:'E':_)
                   | 'L' == x -> return (TLE.encodeUtf16LE bs)
                   | 'B' == x -> return (TLE.encodeUtf16BE bs)
diff --git a/text-locale-encoding.cabal b/text-locale-encoding.cabal
--- a/text-locale-encoding.cabal
+++ b/text-locale-encoding.cabal
@@ -1,5 +1,5 @@
 name:          text-locale-encoding
-version:       0.1
+version:       0.1.0.1
 synopsis:      Encode and decode Text to/from ByteString using TextEncoding
 homepage:      https://github.com/exbb2/text-locale-encoding
 license:       BSD3
@@ -35,5 +35,5 @@
 
     ghc-options: -Wall
 
-    if impl(ghc>=7.2)
+    if flag(trustworthy) && impl(ghc>=7.2)
         cpp-options: -DTRUSTWORTHY=1