diff --git a/proxy/shadowsocks/ota.go b/proxy/shadowsocks/ota.go
index 369f9220..ec3fdb60 100644
--- a/proxy/shadowsocks/ota.go
+++ b/proxy/shadowsocks/ota.go
@@ -49,7 +49,7 @@ func ChunkKeyGenerator(iv []byte) func() []byte {
 	return func() []byte {
 		newKey := make([]byte, 0, len(iv)+4)
 		newKey = append(newKey, iv...)
-		serial.IntToBytes(chunkId, newKey)
+		newKey = serial.IntToBytes(chunkId, newKey)
 		chunkId++
 		return newKey
 	}