diff --git a/src/main/scala/amba/axis/Bundles.scala b/src/main/scala/amba/axis/Bundles.scala
index be107726cab..c8a7832d8e2 100644
--- a/src/main/scala/amba/axis/Bundles.scala
+++ b/src/main/scala/amba/axis/Bundles.scala
@@ -18,10 +18,7 @@ case class AXISIdField  (width: Int) extends SimpleBundleField(AXISId)  (Output(
 case class AXISDestField(width: Int) extends SimpleBundleField(AXISDest)(Output(UInt(width.W)), 0.U)
 case class AXISKeepField(width: Int) extends SimpleBundleField(AXISKeep)(Output(UInt(width.W)), ~0.U(width.W))
 case class AXISStrbField(width: Int) extends SimpleBundleField(AXISStrb)(Output(UInt(width.W)), ~0.U(width.W))
-case class AXISDataField(width: Int) extends BundleField(AXISData) {
-  def data = Output(UInt(width.W))
-  def default(x: UInt): Unit = { x := DontCare }
-}
+case class AXISDataField(width: Int) extends BundleField[UInt](AXISData, Output(UInt(width.W)), _ := DontCare)
 
 class AXISBundleBits(val params: AXISBundleParameters) extends BundleMap(AXISBundle.keys(params)) {
   def last = if (params.hasLast) apply(AXISLast) else true.B
diff --git a/src/main/scala/amba/package.scala b/src/main/scala/amba/package.scala
index 11c9f5e1cea..2af015abd9b 100644
--- a/src/main/scala/amba/package.scala
+++ b/src/main/scala/amba/package.scala
@@ -17,23 +17,18 @@ package object amba {
   }
 
   case object AMBAProt extends ControlKey[AMBAProtBundle]("amba_prot")
-  case class AMBAProtField() extends BundleField(AMBAProt) {
-    def data = Output(new AMBAProtBundle)
-    def default(x: AMBAProtBundle): Unit = {
-      x.bufferable := false.B
-      x.modifiable := false.B
-      x.readalloc  := false.B
-      x.writealloc := false.B
-      x.privileged := true.B
-      x.secure     := true.B
-      x.fetch      := false.B
-    }
-  }
+
+  case class AMBAProtField() extends BundleField[AMBAProtBundle](AMBAProt, Output(new AMBAProtBundle), x => {
+    x.bufferable := false.B
+    x.modifiable := false.B
+    x.readalloc  := false.B
+    x.writealloc := false.B
+    x.privileged := true.B
+    x.secure     := true.B
+    x.fetch      := false.B
+  })
 
   // Used to convert a TileLink corrupt signal into an AMBA user bit
   case object AMBACorrupt extends DataKey[Bool]("corrupt")
-  case class AMBACorruptField() extends BundleField(AMBACorrupt) {
-    def data = Output(Bool())
-    def default(x: Bool): Unit = { x := false.B }
-  }
-}
+  case class AMBACorruptField() extends BundleField[Bool](AMBACorrupt, Output(Bool()), x => x := false.B)
+}
\ No newline at end of file