diff --git a/top/x400/x4xx_core.v b/top/x400/x4xx_core.v
index ad8dc50..f769104 100644
--- a/top/x400/x4xx_core.v
+++ b/top/x400/x4xx_core.v
@@ -417,6 +417,9 @@ module x4xx_core #(
   `ifndef DRAM_CH
     `define DRAM_CH 0
   `endif
+  `ifndef DRAM_BANKS
+    `define DRAM_BANKS 0
+  `endif
   `ifndef DRAM_W
     `define DRAM_W 64
   `endif