diff --git a/lib/default.nix b/lib/default.nix
index a446300..f802a72 100644
--- a/lib/default.nix
+++ b/lib/default.nix
@@ -102,7 +102,7 @@ in rec {
   novaImage = name:
     { gzip ? false, ... }@env:
     boot:
-    pkgs.stdenv.mkDerivation {
+    pkgs.buildPackages.stdenv.mkDerivation {
       name = name + "-nova-image";
       build = compileBoot name env boot;
 
diff --git a/nixos-modules/genode-core.nix b/nixos-modules/genode-core.nix
index aef7172..0a243d2 100644
--- a/nixos-modules/genode-core.nix
+++ b/nixos-modules/genode-core.nix
@@ -267,7 +267,7 @@ in {
 
     # Create the tarball of the store to live in core ROM
     system.build.tarball =
-      pkgs.callPackage "${modulesPath}/../lib/make-system-tarball.nix" {
+      pkgs.buildPackages.callPackage "${modulesPath}/../lib/make-system-tarball.nix" {
         extraInputs = lib.attrsets.mapAttrsToList (_: child: child.package)
           config.genode.init.children;
         contents = erisContents;