diff --git a/pkgs/development/libraries/science/math/magma/default.nix b/pkgs/development/libraries/science/math/magma/default.nix
index b34139e7f484..dbe162c60b34 100644
--- a/pkgs/development/libraries/science/math/magma/default.nix
+++ b/pkgs/development/libraries/science/math/magma/default.nix
@@ -1,8 +1,4 @@
-{ stdenv, fetchurl, cmake, gfortran, cudatoolkit, libpthreadstubs, lapack, blas
-, mklSupport ? false, mkl ? null
-}:
-
-assert !mklSupport || mkl != null;
+{ stdenv, fetchurl, cmake, gfortran, cudatoolkit, libpthreadstubs, lapack, blas }:
 
 with stdenv.lib;
 
@@ -17,13 +13,10 @@ in stdenv.mkDerivation {
     name = "magma-${version}.tar.gz";
   };
 
-  buildInputs = [ gfortran cudatoolkit libpthreadstubs cmake ]
-    ++ (if mklSupport then [ mkl ] else [ lapack blas ]);
+  buildInputs = [ gfortran cudatoolkit libpthreadstubs cmake lapack blas ];
 
   doCheck = false;
 
-  MKLROOT = optionalString mklSupport mkl;
-
   preConfigure = ''
     export CC=${cudatoolkit.cc}/bin/gcc CXX=${cudatoolkit.cc}/bin/g++
   '';