diff --git a/dune/istl/scaledidmatrix.hh b/dune/istl/scaledidmatrix.hh
index 41ab81e3eb4d32272ce1455c2f4a520f1ccb9b22..c0d9a70ada8f9bff3400f6b93f81656f380f0a23 100644
--- a/dune/istl/scaledidmatrix.hh
+++ b/dune/istl/scaledidmatrix.hh
@@ -455,8 +455,8 @@ namespace Dune {
 
   };
 
-  template<class K, int n>
-  void istl_assign_to_fmatrix(FieldMatrix<K,n,n>& fm, const ScaledIdentityMatrix<K,n>& s)
+  template<class M, class K, int n>
+  void istl_assign_to_fmatrix(DenseMatrix<M>& fm, const ScaledIdentityMatrix<K,n>& s)
   {
     fm = K();
     for(int i=0; i<n; ++i)