diff --git a/flake.nix b/flake.nix
index 331320a..1853d48 100644
--- a/flake.nix
+++ b/flake.nix
@@ -39,7 +39,7 @@
             mkdir -p out
 
             # copy systemd
-            cp -r ${self.packages.${system}.systemd.out}/* out/
+            cp -Pr ${self.packages.${system}.systemd.out}/* out/
             pushd out
 
             find . -type d -exec chmod 755 {} \;
@@ -113,8 +113,8 @@
             chmod 644 ./etc/group
 
             # install lib kmod
-            cp ${pkgs.kmod.lib}/lib/* ./usr/lib
-            cp ${pkgs.libbpf.out}/lib/libbpf* ./usr/lib
+            cp -P ${pkgs.kmod.lib}/lib/* ./usr/lib
+            cp -P ${pkgs.libbpf.out}/lib/libbpf* ./usr/lib
 
             # FIXME: remove this
             cat <<EOF > usr/lib/systemd/system/demo.service