diff --git a/pkgs/development/python-modules/tensorflow-tensorboard/default.nix b/pkgs/development/python-modules/tensorflow-tensorboard/default.nix
index b196fc8edce..7840e6de009 100644
--- a/pkgs/development/python-modules/tensorflow-tensorboard/default.nix
+++ b/pkgs/development/python-modules/tensorflow-tensorboard/default.nix
@@ -26,12 +26,16 @@ buildPythonPackage rec {
     sha256 = "19ixs811ndx8qh72dif0ywjss3rv7pf1khsgg6rvfjb9nw8wgjc2";
   } else {
     python = "py2";
-    sha256 = "1mkyb5gn952i4s7fmc9ay4yh74ysrqbiqna6dl1qmahjpbaavbf5";
+    sha256 = "0qpv6jsf6jjvdl95qvarn006kfj5a99mq925d73xg4af50ssvkrf";
   }));
 
-  propagatedBuildInputs = [ numpy werkzeug protobuf
-                            markdown
-                            grpcio absl-py ]; # ++ lib.optional (!isPy3k) futures;
+  propagatedBuildInputs = [
+    numpy
+    werkzeug
+    protobuf
+    markdown
+    grpcio absl-py
+  ] ++ lib.optional (!isPy3k) futures;
 
   meta = with stdenv.lib; {
     description = "TensorFlow's Visualization Toolkit";
diff --git a/pkgs/development/python-modules/tensorflow/bin.nix b/pkgs/development/python-modules/tensorflow/bin.nix
index e1c25d9eca7..03f1e66bf50 100644
--- a/pkgs/development/python-modules/tensorflow/bin.nix
+++ b/pkgs/development/python-modules/tensorflow/bin.nix
@@ -55,7 +55,8 @@ in buildPythonPackage rec {
   in fetchurl dls.${key};
 
   propagatedBuildInputs = [  protobuf numpy termcolor grpcio six astor absl-py gast tensorflow-estimator tensorflow-tensorboard keras-applications keras-preprocessing ]
-                 ++ lib.optional (!isPy3k) mock;
+                 ++ lib.optional (!isPy3k) mock
+                 ++ lib.optionals (pythonOlder "3.4") [ backports_weakref ];
 
   # Upstream has a pip hack that results in bin/tensorboard being in both tensorflow
   # and the propageted input tensorflow-tensorboard which causes environment collisions.