diff --git a/src/main/scala/uncore/tilelink2/RegField.scala b/src/main/scala/uncore/tilelink2/RegField.scala
index 3a49659f..7a51cb1f 100644
--- a/src/main/scala/uncore/tilelink2/RegField.scala
+++ b/src/main/scala/uncore/tilelink2/RegField.scala
@@ -110,12 +110,12 @@ object RegField
   // The bytes can be individually written, as they are one byte per field
   def bytes(x: UInt, base: Int = 0, beatBytes: Int = 4): Seq[RegField.Map] = {
     require (x.getWidth % 8 == 0)
+    val bytes = Seq.tabulate(x.getWidth/8) { i => x(8*(i+1)-1, 8*i) }
+    val wires = bytes.map { b => Wire(init = b) }
+    x := Cat(wires.reverse)
     Seq.tabulate(x.getWidth/8) { i =>
-      RegField(8, x(8*(i+1)-1, 8*i), RegWriteFn { (valid, data) =>
-        when (valid) {
-          val mask = ~UInt(BigInt(0xff) << 8*i, width = x.getWidth)
-          x := (x & mask) | (data & UInt(0xff)) << 8*i
-        }
+      RegField(8, bytes(i), RegWriteFn { (valid, data) =>
+        when (valid) { wires(i) := data }
         Bool(true)
       })
     }.grouped(beatBytes).toSeq.zipWithIndex.map { case (reg, i) =>