diff --git a/pkgs/development/python-modules/unicorn/default.nix b/pkgs/development/python-modules/unicorn/default.nix
index b20843d0fc29..de317ec1844e 100644
--- a/pkgs/development/python-modules/unicorn/default.nix
+++ b/pkgs/development/python-modules/unicorn/default.nix
@@ -1,4 +1,4 @@
-{ stdenv, buildPythonPackage, fetchPypi, isPy3k }:
+{ stdenv, buildPackages, buildPythonPackage, fetchPypi, isPy3k }:
 
 buildPythonPackage rec {
   name  = "${pname}-${version}";
@@ -10,7 +10,8 @@ buildPythonPackage rec {
     sha256 = "0a5b4vh734b3wfkgapzzf8x18rimpmzvwwkly56da84n27wfw9bg";
   };
 
-  disabled = isPy3k;
+  # needs python2 at build time
+  PYTHON="${buildPackages.python2.interpreter}";
 
   setupPyBuildFlags = [ "--plat-name" "linux" ];