diff --git a/artiq-fast/artiq-board.nix b/artiq-fast/artiq-board.nix
index d2f58f8..7850c4d 100644
--- a/artiq-fast/artiq-board.nix
+++ b/artiq-fast/artiq-board.nix
@@ -55,7 +55,7 @@ let
   boardModule =
     # Board packages are Python modules so that they get added to the ARTIQ Python
     # environment, and artiq_flash finds them.
-    pkgs.python3Packages.toPythonModule (pkgs.stdenv.mkDerivation {
+    pkgs.stdenv.mkDerivation {
       name = "${name}-firmware";
       inherit version src;
       phases = [ "buildPhase" "installCheckPhase" "installPhase" "checkPhase" ];
@@ -91,7 +91,7 @@ let
         fi
         ${extraInstallCommands}
         '';
-    });
+    };
 
   identifierStr = "${version};${variant}";
   identifiers = import (
@@ -180,8 +180,9 @@ let
     '';
   };
 in
-pkgs.buildEnv rec {
-  inherit name;
-  paths = [ boardModule vivadoOutput ];
-  pathsToLink = [ "/${installPath}" ];
-}
+pkgs.python3Packages.toPythonModule (
+  pkgs.buildEnv rec {
+    inherit name;
+    paths = [ boardModule vivadoOutput ];
+    pathsToLink = [ "/${installPath}" ];
+  })