diff --git a/ebpfcat/ethercat.py b/ebpfcat/ethercat.py
index 874a6f77185b67be76255bdeac9d10f7597d99d4..f8c8fb2897103a77e2c28c41aed2fd3df4705dd6 100644
--- a/ebpfcat/ethercat.py
+++ b/ebpfcat/ethercat.py
@@ -230,9 +230,9 @@ class Packet:
                             cmd.value, *dgram, len(data) | FOLLOW, 0))
             ret.append(data)
             ret.append(b"\0\0")
-        ret.append(pack("<BBiHHH", ECCmd.NOP.value, 0, index, 0, 0, 0))
-        if self.size < 34:
-            ret.append(b"\0" * (34 - self.size))
+        ret.append(pack("<BBiHHBH", 0, 0xf6, index, 1, 0, 1, 0))
+        if self.size < 33:
+            ret.append(b"\0" * (33 - self.size))
         return b''.join(ret)
 
     def __str__(self):