diff --git a/pkgs/development/python-modules/pyhepmc/default.nix b/pkgs/development/python-modules/pyhepmc/default.nix
index e466f800107..acb5c964878 100644
--- a/pkgs/development/python-modules/pyhepmc/default.nix
+++ b/pkgs/development/python-modules/pyhepmc/default.nix
@@ -1,6 +1,7 @@
 { stdenv
 , buildPythonPackage
 , fetchPypi
+, fetchFromBitbucket
 , isPy3k
 , fetchurl
 , pkgs
@@ -17,6 +18,18 @@ buildPythonPackage rec {
     sha256 = "1210fd7e20d4abc1d9166147a9f7645a2a58b655fe030ad54ab3ea0d0c6e0834";
   };
 
+  srcMissing = fetchFromBitbucket {
+    owner = "andybuckley";
+    repo = "pyhepmc";
+    rev = "pyhepmc-1.0.0";
+    sha256 = "0vxad143pz45q94w5p0dycpk24insdsv1m5k867y56xy24bi0d4w";
+  };
+
+  prePatch = ''
+    cp -r $srcMissing/hepmc .
+    chmod +w hepmc
+  '';
+
   patches = [
     # merge PR https://bitbucket.org/andybuckley/pyhepmc/pull-requests/1/add-incoming-outgoing-generators-for/diff
     ./pyhepmc_export_edges.patch
@@ -26,11 +39,11 @@ buildPythonPackage rec {
 
   # regenerate python wrapper
   preConfigure = ''
-    rm hepmc/hepmcwrap.py
     swig -c++ -I${pkgs.hepmc}/include -python hepmc/hepmcwrap.i
   '';
 
-  buildInputs = [ pkgs.swig pkgs.hepmc ];
+  nativeBuildInputs = [ pkgs.swig ];
+  buildInputs = [ pkgs.hepmc ];
 
   HEPMCPATH = pkgs.hepmc;