diff --git a/instances/heimdall/configuration.nix b/instances/heimdall/configuration.nix
index 075f89c..11bb8be 100644
--- a/instances/heimdall/configuration.nix
+++ b/instances/heimdall/configuration.nix
@@ -105,6 +105,7 @@ in
         permit_join = true;
         serial = {
           port = "/dev/serial/by-id/usb-1a86_USB_Serial-if00-port0";
+          adapter = "zstack";
         };
       };
     };