diff --git a/src/main/scala/rocket/RocketCore.scala b/src/main/scala/rocket/RocketCore.scala
index 8accdf817c..1521f7af4b 100644
--- a/src/main/scala/rocket/RocketCore.scala
+++ b/src/main/scala/rocket/RocketCore.scala
@@ -340,7 +340,7 @@ class Rocket(tile: RocketTile)(implicit p: Parameters) extends CoreModule()(p)
     val v_decode = rocketParams.vector.get.decoder(p)
     v_decode.io.inst := id_inst(0)
     v_decode.io.vconfig := csr.io.vector.get.vconfig
-    when (v_decode.io.legal) {
+    when (v_decode.io.legal && !csr.io.vector.get.vconfig.vtype.vill) {
       id_ctrl.legal := true.B
       id_ctrl.fp := v_decode.io.fp
       id_ctrl.rocc := false.B