diff --git a/litex/build/sim/verilator.py b/litex/build/sim/verilator.py
index 28a4c5676..8e1208281 100644
--- a/litex/build/sim/verilator.py
+++ b/litex/build/sim/verilator.py
@@ -187,6 +187,7 @@ class SimVerilatorToolchain:
             serial           = "console",
             build            = True,
             run              = True,
+            backend          = None,
             threads          = 1,
             verbose          = True,
             sim_config       = None,