diff --git a/nixos/modules/virtualisation/container-config.nix b/nixos/modules/virtualisation/container-config.nix
index 6ff6bdd30c2..0966ef84827 100644
--- a/nixos/modules/virtualisation/container-config.nix
+++ b/nixos/modules/virtualisation/container-config.nix
@@ -18,7 +18,7 @@ with lib;
     services.openssh.startWhenNeeded = mkDefault true;
 
     # Shut up warnings about not having a boot loader.
-    system.build.installBootLoader = "${pkgs.coreutils}/bin/true";
+    system.build.installBootLoader = lib.mkDefault "${pkgs.coreutils}/bin/true";
 
     # Not supported in systemd-nspawn containers.
     security.audit.enable = false;