diff --git a/nixos/tests/all-tests.nix b/nixos/tests/all-tests.nix
index 753cefb9bbe0..504aabae0d99 100644
--- a/nixos/tests/all-tests.nix
+++ b/nixos/tests/all-tests.nix
@@ -699,7 +699,7 @@ in {
   nixops = handleTest ./nixops/default.nix {};
   nixos-generate-config = handleTest ./nixos-generate-config.nix {};
   nixos-rebuild-install-bootloader = handleTestOn ["x86_64-linux"] ./nixos-rebuild-install-bootloader.nix {};
-  nixos-rebuild-specialisations = handleTestOn ["x86_64-linux"] ./nixos-rebuild-specialisations.nix {};
+  nixos-rebuild-specialisations = runTestOn ["x86_64-linux"] ./nixos-rebuild-specialisations.nix;
   nixos-rebuild-target-host = runTest ./nixos-rebuild-target-host.nix;
   nixpkgs = pkgs.callPackage ../modules/misc/nixpkgs/test.nix { inherit evalMinimalConfig; };
   nixseparatedebuginfod = handleTest ./nixseparatedebuginfod.nix {};
diff --git a/nixos/tests/nixos-rebuild-specialisations.nix b/nixos/tests/nixos-rebuild-specialisations.nix
index ab67bbaba676..f12d0fc48ce9 100644
--- a/nixos/tests/nixos-rebuild-specialisations.nix
+++ b/nixos/tests/nixos-rebuild-specialisations.nix
@@ -1,6 +1,10 @@
-import ./make-test-python.nix ({ pkgs, ... }: {
+{ hostPkgs, ... }: {
   name = "nixos-rebuild-specialisations";
 
+  # TODO: remove overlay from  nixos/modules/profiles/installation-device.nix
+  #        make it a _small package instead, then remove pkgsReadOnly = false;.
+  node.pkgsReadOnly = false;
+
   nodes = {
     machine = { lib, pkgs, ... }: {
       imports = [
@@ -32,7 +36,7 @@ import ./make-test-python.nix ({ pkgs, ... }: {
 
   testScript =
     let
-      configFile = pkgs.writeText "configuration.nix" ''
+      configFile = hostPkgs.writeText "configuration.nix" ''
         { lib, pkgs, ... }: {
           imports = [
             ./hardware-configuration.nix
@@ -119,4 +123,4 @@ import ./make-test-python.nix ({ pkgs, ... }: {
           machine.fail("nixos-rebuild boot --specialisation foo")
           machine.fail("nixos-rebuild boot -c foo")
     '';
-})
+}