diff --git a/src/main/scala/uncore/tilelink2/Filter.scala b/src/main/scala/uncore/tilelink2/Filter.scala
index c851f3f1..d22d56b7 100644
--- a/src/main/scala/uncore/tilelink2/Filter.scala
+++ b/src/main/scala/uncore/tilelink2/Filter.scala
@@ -14,7 +14,10 @@ class TLFilter(select: AddressSet) extends LazyModule
     managerFn = { case Seq(mp) =>
       mp.copy(managers = mp.managers.map { m =>
         val filtered = m.address.map(_.intersect(select)).flatten
-        val cap = TransferSizes(1, select.alignment.toInt)
+        val alignment = select.alignment /* alignment 0 means 'select' selected everything */
+        val maxTransfer = 1 << 30
+        val capTransfer = if (alignment == 0 || alignment > maxTransfer) maxTransfer else alignment.toInt
+        val cap = TransferSizes(1, capTransfer)
         if (filtered.isEmpty) { None } else {
           Some(m.copy(
             address            = filtered,