diff --git a/Graphics/Rendering/OpenGL/GL/VertexSpec.hs b/Graphics/Rendering/OpenGL/GL/VertexSpec.hs
--- a/Graphics/Rendering/OpenGL/GL/VertexSpec.hs
+++ b/Graphics/Rendering/OpenGL/GL/VertexSpec.hs
@@ -1072,4 +1072,4 @@
 
 maxTextureUnit :: GettableStateVar TextureUnit
 maxTextureUnit =
-   makeGettableStateVar (getEnum1 unmarshalTextureUnit GetMaxTextureUnits)
+   makeGettableStateVar (getEnum1 (TextureUnit . fromIntegral) GetMaxTextureUnits)
diff --git a/OpenGL.cabal b/OpenGL.cabal
--- a/OpenGL.cabal
+++ b/OpenGL.cabal
@@ -1,5 +1,5 @@
 name: OpenGL
-version: 2.4.0.0
+version: 2.4.0.1
 license: BSD3
 license-file: LICENSE
 maintainer: Sven Panne <sven.panne@aedion.de>
