diff --git a/src/main/scala/coreplex/RocketCoreplex.scala b/src/main/scala/coreplex/RocketCoreplex.scala
index feee369e..b57f0f2c 100644
--- a/src/main/scala/coreplex/RocketCoreplex.scala
+++ b/src/main/scala/coreplex/RocketCoreplex.scala
@@ -46,19 +46,19 @@ trait HasRocketTiles extends HasSystemBus
       case SynchronousCrossing(params) => {
         val wrapper = LazyModule(new SyncRocketTile(tp, i)(pWithExtra))
         sbus.fromSyncTiles(params, tp.externalMasterBuffers, tp.name) :=* wrapper.masterNode
-        wrapper.slaveNode :*= pbus.bufferToSlaves
+        wrapper.slaveNode :*= pbus.toSyncSlaves(tp.name, tp.externalSlaveBuffers)
         wrapper
       }
       case AsynchronousCrossing(depth, sync) => {
         val wrapper = LazyModule(new AsyncRocketTile(tp, i)(pWithExtra))
         sbus.fromAsyncTiles(depth, sync, tp.externalMasterBuffers, tp.name) :=* wrapper.masterNode
-        wrapper.slaveNode :*= pbus.toAsyncSlaves(sync, tp.name)
+        wrapper.slaveNode :*= pbus.toAsyncSlaves(sync, tp.name, tp.externalSlaveBuffers)
         wrapper
       }
       case RationalCrossing(direction) => {
         val wrapper = LazyModule(new RationalRocketTile(tp, i)(pWithExtra))
         sbus.fromRationalTiles(direction, tp.externalMasterBuffers, tp.name) :=* wrapper.masterNode
-        wrapper.slaveNode :*= pbus.toRationalSlaves(tp.name)
+        wrapper.slaveNode :*= pbus.toRationalSlaves(tp.name, tp.externalSlaveBuffers)
         wrapper
       }
     }
diff --git a/src/main/scala/tile/RocketTile.scala b/src/main/scala/tile/RocketTile.scala
index ea27e584..a98917b9 100644
--- a/src/main/scala/tile/RocketTile.scala
+++ b/src/main/scala/tile/RocketTile.scala
@@ -20,7 +20,8 @@ case class RocketTileParams(
     dataScratchpadBytes: Int = 0,
     boundaryBuffers: Boolean = false,
     name: Option[String] = Some("tile"),
-    externalMasterBuffers: Int = 0) extends TileParams {
+    externalMasterBuffers: Int = 0,
+    externalSlaveBuffers: Int = 0) extends TileParams {
   require(icache.isDefined)
   require(dcache.isDefined)
 }