diff --git a/rdmnet/pdu.h b/rdmnet/pdu.h
index c9e79c3..e3c609c 100644
--- a/rdmnet/pdu.h
+++ b/rdmnet/pdu.h
@@ -35,11 +35,15 @@ public:
     : ACN::PDU::Pdu(vector_size)
   {
     // RDMnet PDU flags always 0xF
-    flags_.hasVector = true;
-    flags_.hasLength = true;
-    flags_.hasHeader = true;
-    flags_.hasData   = true;
+    flags_.set(0xF0);
   }
+
+  virtual void iStream(ACN::PDU::Stream stream) override
+  {
+    ACN::PDU::Pdu::iStream(stream);
+    if ((uint8_t)flags_ != 0xf0)
+        stream_->setstate(std::ios_base::failbit);
+  };
 };