diff --git a/car.capnp b/car.capnp
index 745389232537f1..58ff3fb42e95cb 100644
--- a/car.capnp
+++ b/car.capnp
@@ -477,5 +477,6 @@ struct CarParams {
   enum FingerprintSource {
     can @0;
     fw @1;
+    fixed @2;
   }
 }