diff --git a/nixos/modules/hardware/facter/system.nix b/nixos/modules/hardware/facter/system.nix
index 02e329f8e162..ef51b0e44f1d 100644
--- a/nixos/modules/hardware/facter/system.nix
+++ b/nixos/modules/hardware/facter/system.nix
@@ -5,11 +5,11 @@
   ...
 }:
 {
-  # Skip setting hostPlatform in test VMs where it's read-only
-  # Tests have virtualisation.test options and import read-only.nix
-  config.nixpkgs = lib.optionalAttrs (!(options ? virtualisation.test)) {
-    hostPlatform = lib.mkIf (
-      config.hardware.facter.report.system or null != null && !options.nixpkgs.pkgs.isDefined
-    ) (lib.mkDefault config.hardware.facter.report.system);
-  };
+  # Skip setting hostPlatform if it's read-only
+  nixpkgs =
+    lib.optionalAttrs
+      (config.hardware.facter.report.system or null != null && !options.nixpkgs.hostPlatform.readOnly)
+      {
+        hostPlatform = lib.mkDefault config.hardware.facter.report.system;
+      };
 }