diff --git a/difftest/dpi_t1rocketemu/src/drive.rs b/difftest/dpi_t1rocketemu/src/drive.rs
index fc460eeb5..6f48c67d8 100644
--- a/difftest/dpi_t1rocketemu/src/drive.rs
+++ b/difftest/dpi_t1rocketemu/src/drive.rs
@@ -161,7 +161,7 @@ impl Driver {
     );
 
     assert!(
-      !(size < bus_size && arlen > 0),
+      !(size < bus_size && arlen < 0),
       "narrow burst not supported, axsize={arsize}, axlen={arlen}, data_width={data_width}"
     );
     let transaction_size = bus_size * (arlen + 1);