diff --git a/default.nix b/default.nix
index 7c9dad8..0f050ff 100644
--- a/default.nix
+++ b/default.nix
@@ -1,6 +1,7 @@
 let
   pkgs = import <nixpkgs> { overlays = [ (import ./nix/mozilla-overlay.nix) ]; };
   rustPlatform = (import ./nix/rust-platform.nix { inherit pkgs; });
+  cargo-xbuild = (pkgs.cargo-xbuild.overrideAttrs(oa: { patches = oa.patches ++ [ ./xbuild_writable_lockfile.diff ]; } ));
   cargoSha256Experiments = "0ijb3ma7mip48ayc3hilma42rwlz3krb755klmnwwwvxhdhw29w2";
   cargoSha256SZL = "0shz0kzjnmqvwy68km71awn7krn1109nanyckhzvrxy1l1jxg2rd";
   build-crate = name: crate: features: cargoSha256:
@@ -10,9 +11,7 @@ let
       src = ./.;
       inherit cargoSha256;
 
-      nativeBuildInputs = [
-        (pkgs.cargo-xbuild.overrideAttrs(oa: { patches = oa.patches ++ [ ./xbuild_writable_lockfile.diff ]; } ))
-      ];
+      nativeBuildInputs = [ cargo-xbuild ];
       buildPhase = ''
         export XARGO_RUST_SRC="${rustPlatform.rust.rustc.src}/library"
         export CARGO_HOME=$(mktemp -d cargo-home.XXX)
@@ -34,6 +33,7 @@ let
     };
 in
   {
+    inherit cargo-xbuild;
     zc706-experiments = build-crate "zc706-experiments" "experiments" "target_zc706" cargoSha256Experiments;
     cora-experiments = build-crate "cora-experiments" "experiments" "target_cora_z7_10" cargoSha256Experiments;
     redpitaya-experiments = build-crate "redpitaya-experiments" "experiments" "target_redpitaya" cargoSha256Experiments;
diff --git a/shell.nix b/shell.nix
index 52ec568..1ef6793 100644
--- a/shell.nix
+++ b/shell.nix
@@ -1,6 +1,7 @@
 let
   pkgs = import <nixpkgs> { overlays = [ (import ./nix/mozilla-overlay.nix) ]; };
   rustPlatform = (import ./nix/rust-platform.nix { inherit pkgs; });
+  cargo-xbuild = (import ./default.nix).cargo-xbuild;
 in
   pkgs.stdenv.mkDerivation {
     name = "zynq-env";
@@ -8,7 +9,7 @@ in
       rustPlatform.rust.rustc
       rustPlatform.rust.cargo
       pkgs.cacert
-      (pkgs.cargo-xbuild.overrideAttrs(oa: { patches = oa.patches ++ [ ./xbuild_writable_lockfile.diff ]; } ))
+      cargo-xbuild
 
       pkgs.openocd pkgs.gdb
       pkgs.openssh pkgs.rsync