diff --git a/src/main/scala/tile/RocketTile.scala b/src/main/scala/tile/RocketTile.scala
index 7323a30b..60b50738 100644
--- a/src/main/scala/tile/RocketTile.scala
+++ b/src/main/scala/tile/RocketTile.scala
@@ -177,7 +177,7 @@ abstract class RocketTileWrapper(rtp: RocketTileParams, hartid: Int)(implicit p:
 
   def optionalMasterBuffer(in: TLOutwardNode): TLOutwardNode = {
     if (rtp.boundaryBuffers) {
-      val mbuf = LazyModule(new TLBuffer(BufferParams.none, BufferParams.flow, BufferParams.none, BufferParams.flow, BufferParams.default))
+      val mbuf = LazyModule(new TLBuffer(BufferParams.none, BufferParams.flow, BufferParams.none, BufferParams.flow, BufferParams(1)))
       mbuf.node :=* in
       mbuf.node
     } else {