diff --git a/shell.nix b/shell.nix
index 64077107a..61664096a 100644
--- a/shell.nix
+++ b/shell.nix
@@ -1,7 +1,7 @@
 with import <nixpkgs> {};
 
 let
-  myPython = python36.withPackages(p: [p.pytest p.black p.isort p.requests p.mnemonic p.construct p.pyblake2 p.mock p.ecdsa p.click p.libusb1]);
+  myPython = python36.withPackages(p: [p.pytest p.black p.isort p.requests p.mnemonic p.construct p.pyblake2 p.mock p.ecdsa p.click p.libusb1 p.protobuf]);
 in
   stdenv.mkDerivation {
     name = "python-trezor-dev";