diff --git a/nixos-modules/genode-core.nix b/nixos-modules/genode-core.nix
index 6447e2c..73759a8 100644
--- a/nixos-modules/genode-core.nix
+++ b/nixos-modules/genode-core.nix
@@ -287,10 +287,13 @@ in {
           (with pkgs.genodePackages;
             config.genode.core.basePackages ++ storeBackendInputs
             ++ [ init cached_fs_rom jitter_sponge report_rom vfs ]
-            ++ coreInputs)) + ''# [ { mapKey = "romModules", mapValue = [ ''
-          + (toString
-            (mapAttrsToList (k: v: '', { mapKey = "${k}", mapValue = "${v}" }'')
-              config.genode.boot.romModules)) + " ] } ]");
+            ++ coreInputs))
+          + lib.optionalString (config.genode.boot.romModules != { }) ''
+            # [ { mapKey = "romModules", mapValue = [ ${
+              toString (mapAttrsToList
+                (k: v: '', { mapKey = "${k}", mapValue = "${v}" }'')
+                config.genode.boot.romModules)
+            }] } ]'');
 
       storeRomPolicies = mapAttrsToList
         (name: value: '', { mapKey = "${name}", mapValue = "${value}" }'')