diff --git a/.ci/instantiate-all.nix b/.ci/instantiate-all.nix
index b29bbbd0..dc3a8ced 100644
--- a/.ci/instantiate-all.nix
+++ b/.ci/instantiate-all.nix
@@ -44,6 +44,9 @@ let
     ;
 
   flattened =
+    # If this fails, evaluations probably don't receive additional configuration
+    # configuring nixpkgs.localSystem.
+    assert devices."device.asus-z00t.aarch64-linux" != devices."device.asus-z00t.x86_64-linux";
     release //
     devices //
     # We could try and do something smart to unwrap two levels of attrsets
diff --git a/default.nix b/default.nix
index db355671..f639b3c5 100644
--- a/default.nix
+++ b/default.nix
@@ -46,6 +46,7 @@ let
   eval = evalWith {
     device = final_device;
     modules = configuration;
+    inherit additionalConfiguration;
   };
 
   # This is used by the `-A installer` shortcut.