diff --git a/rocket/src/main/scala/decode.scala b/rocket/src/main/scala/decode.scala
index 7e0b8544..c6e8e6be 100644
--- a/rocket/src/main/scala/decode.scala
+++ b/rocket/src/main/scala/decode.scala
@@ -9,7 +9,7 @@ object DecodeLogic
     val lit = b.litOf
     if (lit.isZ) {
       var (bits, mask, swidth) = Literal.parseLit(lit.toString)
-      new Term(BigInt(bits, 2), BigInt(2).pow(lit.width)-(BigInt(mask, 2)+1))
+      new Term(BigInt(bits, 2), BigInt(2).pow(lit.needWidth())-(BigInt(mask, 2)+1))
     } else {
       new Term(lit.value)
     }
diff --git a/rocket/src/main/scala/util.scala b/rocket/src/main/scala/util.scala
index 82ead46c..407fc1d1 100644
--- a/rocket/src/main/scala/util.scala
+++ b/rocket/src/main/scala/util.scala
@@ -163,8 +163,8 @@ class FlowThroughSerializer[T <: HasTileLinkData](gen: LogicalNetworkIO[T], n: I
     val cnt = UInt(OUTPUT, log2Up(n))
     val done = Bool(OUTPUT)
   }
-  require(io.in.bits.payload.data.width % n == 0)
-  val narrowWidth = io.in.bits.payload.data.width / n
+  require(io.in.bits.payload.data.needWidth() % n == 0)
+  val narrowWidth = io.in.bits.payload.data.needWidth() / n
   val cnt = Reg(init=UInt(0, width = log2Up(n)))
   val wrap = cnt === UInt(n-1)
   val rbits = Reg(init=io.in.bits)