diff --git a/Data/ByteArray.hs b/Data/ByteArray.hs
--- a/Data/ByteArray.hs
+++ b/Data/ByteArray.hs
@@ -228,7 +228,7 @@
 hashByteArray arr =
     unsafePerformIO $
     withArrayPtr arr $ \ptr ->
-    H.hashPtr ptr 0 (length arr)
+    H.hashPtr ptr (length arr)
 
 #define deriveElt(Typ) \
 instance Elt Typ where { \
diff --git a/smallarray.cabal b/smallarray.cabal
--- a/smallarray.cabal
+++ b/smallarray.cabal
@@ -3,7 +3,7 @@
 -- See the Haskell package versioning policy
 -- (http://www.haskell.org/haskellwiki/Package_versioning_policy) for
 -- standards guiding when and how versions should be incremented.
-Version:             0.2.0
+Version:             0.2.1
 
 Synopsis:            low-level unboxed arrays, with minimal features.