diff --git a/.gitignore b/.gitignore
index f2ecd3c0f..791e850fb 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 .idea
 vendor/
+.DS_Store
\ No newline at end of file
diff --git a/binary/pool.go b/binary/pool.go
index 305ae7848..16fb0e808 100644
--- a/binary/pool.go
+++ b/binary/pool.go
@@ -26,7 +26,7 @@ func SelectWriter() *Writer {
 func PutWriter(w *Writer) {
 	// See https://golang.org/issue/23199
 	const maxSize = 1 << 16
-	if w.Cap() < maxSize { // 对于大Buffer直接丢弃
+	if (*bytes.Buffer)(w).Cap() < maxSize { // 对于大Buffer直接丢弃
 		w.Reset()
 		bufferPool.Put(w)
 	}
diff --git a/binary/writer.go b/binary/writer.go
index 19642c819..02c626457 100644
--- a/binary/writer.go
+++ b/binary/writer.go
@@ -4,8 +4,6 @@ import (
 	"bytes"
 	"encoding/binary"
 	"encoding/hex"
-
-	"github.com/Mrs4s/MiraiGo/utils"
 )
 
 // Writer 写入
@@ -15,7 +13,7 @@ func NewWriterF(f func(writer *Writer)) []byte {
 	w := SelectWriter()
 	f(w)
 	b := append([]byte(nil), w.Bytes()...)
-	PutWriter(w)
+	w.put()
 	return b
 }
 
@@ -23,7 +21,40 @@ func NewWriterF(f func(writer *Writer)) []byte {
 func OpenWriterF(f func(*Writer)) (b []byte, cl func()) {
 	w := SelectWriter()
 	f(w)
-	return w.Bytes(), func() { PutWriter(w) }
+	return w.Bytes(), w.put
+}
+
+func (w *Writer) AllocUInt16Head() (pos int) {
+	pos = (*bytes.Buffer)(w).Len()
+	(*bytes.Buffer)(w).Write([]byte{0, 0})
+	return
+}
+
+/*
+func (w *Writer) WriteUInt16HeadAt(pos int) {
+	newdata := (*bytes.Buffer)(w).Bytes()[pos:]
+	binary.BigEndian.PutUint16(newdata, uint16(len(newdata)))
+}
+*/
+
+func (w *Writer) WriteUInt16HeadUsingTotalBufferLenAt(pos int) {
+	binary.BigEndian.PutUint16((*bytes.Buffer)(w).Bytes()[pos:], uint16((*bytes.Buffer)(w).Len()))
+}
+
+func (w *Writer) WriteUInt16HeadExcludeSelfAt(pos int) {
+	newdata := (*bytes.Buffer)(w).Bytes()[pos:]
+	binary.BigEndian.PutUint16(newdata, uint16(len(newdata)-2))
+}
+
+func (w *Writer) AllocUInt32Head() (pos int) {
+	pos = (*bytes.Buffer)(w).Len()
+	(*bytes.Buffer)(w).Write([]byte{0, 0, 0, 0})
+	return
+}
+
+func (w *Writer) WriteUInt32HeadAt(pos int) {
+	newdata := (*bytes.Buffer)(w).Bytes()[pos:]
+	binary.BigEndian.PutUint32(newdata, uint32(len(newdata)))
 }
 
 func (w *Writer) Write(b []byte) {
@@ -35,8 +66,8 @@ func (w *Writer) WriteHex(h string) {
 	w.Write(b)
 }
 
-func (w *Writer) WriteByte(b byte) {
-	(*bytes.Buffer)(w).WriteByte(b)
+func (w *Writer) WriteByte(b byte) error {
+	return (*bytes.Buffer)(w).WriteByte(b)
 }
 
 func (w *Writer) WriteUInt16(v uint16) {
@@ -58,13 +89,13 @@ func (w *Writer) WriteUInt64(v uint64) {
 }
 
 func (w *Writer) WriteString(v string) {
-	payload := utils.S2B(v)
-	w.WriteUInt32(uint32(len(payload) + 4))
-	w.Write(payload)
+	w.WriteUInt32(uint32(len(v) + 4))
+	(*bytes.Buffer)(w).WriteString(v)
 }
 
 func (w *Writer) WriteStringShort(v string) {
-	w.WriteBytesShort(utils.S2B(v))
+	w.WriteUInt16(uint16(len(v)))
+	(*bytes.Buffer)(w).WriteString(v)
 }
 
 func (w *Writer) WriteBool(b bool) {
@@ -86,27 +117,6 @@ func (w *Writer) WriteIntLvPacket(offset int, f func(*Writer)) {
 	cl()
 }
 
-func (w *Writer) WriteUniPacket(commandName string, sessionId, extraData, body []byte) {
-	w1 := SelectWriter()
-	{ // WriteIntLvPacket
-		w1.WriteString(commandName)
-		w1.WriteUInt32(8)
-		w1.Write(sessionId)
-		if len(extraData) == 0 {
-			w1.WriteUInt32(0x04)
-		} else {
-			w1.WriteUInt32(uint32(len(extraData) + 4))
-			w1.Write(extraData)
-		}
-	}
-	data := w1.Bytes()
-	w.WriteUInt32(uint32(len(data) + 4))
-	w.Write(data)
-	PutWriter(w1)
-	w.WriteUInt32(uint32(len(body) + 4)) // WriteIntLvPacket
-	w.Write(body)
-}
-
 func (w *Writer) WriteBytesShort(data []byte) {
 	w.WriteUInt16(uint16(len(data)))
 	w.Write(data)
@@ -124,10 +134,6 @@ func (w *Writer) Bytes() []byte {
 	return (*bytes.Buffer)(w).Bytes()
 }
 
-func (w *Writer) Cap() int {
-	return (*bytes.Buffer)(w).Cap()
-}
-
 func (w *Writer) Reset() {
 	(*bytes.Buffer)(w).Reset()
 }
@@ -135,3 +141,7 @@ func (w *Writer) Reset() {
 func (w *Writer) Grow(n int) {
 	(*bytes.Buffer)(w).Grow(n)
 }
+
+func (w *Writer) put() {
+	PutWriter(w)
+}
diff --git a/client/builders.go b/client/builders.go
index 8e08165f2..b762448d2 100644
--- a/client/builders.go
+++ b/client/builders.go
@@ -1097,12 +1097,7 @@ func (c *QQClient) buildGroupAdminSetPacket(groupCode, member int64, flag bool)
 	b, cl := binary.OpenWriterF(func(w *binary.Writer) {
 		w.WriteUInt32(uint32(groupCode))
 		w.WriteUInt32(uint32(member))
-		w.WriteByte(func() byte {
-			if flag {
-				return 1
-			}
-			return 0
-		}())
+		w.WriteBool(flag)
 	})
 	payload := c.packOIDBPackage(1372, 1, b)
 	cl()
diff --git a/client/internal/network/transport.go b/client/internal/network/transport.go
index e5dc468c9..cf0b0317f 100644
--- a/client/internal/network/transport.go
+++ b/client/internal/network/transport.go
@@ -19,9 +19,7 @@ type Transport struct {
 	// conn *TCPListener
 }
 
-func (t *Transport) packBody(req *Request) []byte {
-	w := binary.SelectWriter()
-	defer binary.PutWriter(w)
+func (t *Transport) packBody(req *Request, w *binary.Writer) {
 	w.WriteIntLvPacket(4, func(writer *binary.Writer) {
 		if req.Type == RequestTypeLogin {
 			writer.WriteUInt32(uint32(req.SequenceID))
@@ -58,7 +56,6 @@ func (t *Transport) packBody(req *Request) []byte {
 	})
 	// w.WriteUInt32(uint32(len(req.Body) + 4))
 	// w.Write(req.Body)
-	return append([]byte(nil), w.Bytes()...)
 }
 
 // PackPacket packs a packet.
@@ -67,16 +64,10 @@ func (t *Transport) PackPacket(req *Request) []byte {
 	if len(t.Sig.D2) == 0 {
 		req.EncryptType = EncryptTypeEmptyKey
 	}
-	body := t.packBody(req)
-	// encrypt body
-	switch req.EncryptType {
-	case EncryptTypeD2Key:
-		body = binary.NewTeaCipher(t.Sig.D2Key).Encrypt(body)
-	case EncryptTypeEmptyKey:
-		body = binary.NewTeaCipher(emptyKey).Encrypt(body)
-	}
 
-	head := binary.NewWriterF(func(w *binary.Writer) {
+	return binary.NewWriterF(func(w *binary.Writer) {
+		pos := w.AllocUInt32Head()
+		// vvv w.Write(head) vvv
 		w.WriteUInt32(uint32(req.Type))
 		w.WriteByte(byte(req.EncryptType))
 		switch req.Type {
@@ -93,14 +84,24 @@ func (t *Transport) PackPacket(req *Request) []byte {
 		}
 		w.WriteByte(0x00)
 		w.WriteString(strconv.FormatInt(req.Uin, 10))
+		// ^^^ w.Write(head) ^^^
+		w.Write(binary.NewWriterF(func(w *binary.Writer) {
+			// encrypt body
+			switch req.EncryptType {
+			case EncryptTypeD2Key:
+				wt, cl := binary.OpenWriterF(func(w *binary.Writer) { t.packBody(req, w) })
+				w.EncryptAndWrite(t.Sig.D2Key, wt)
+				cl()
+			case EncryptTypeEmptyKey:
+				wt, cl := binary.OpenWriterF(func(w *binary.Writer) { t.packBody(req, w) })
+				w.EncryptAndWrite(emptyKey, wt)
+				cl()
+			default:
+				t.packBody(req, w)
+			}
+		}))
+		w.WriteUInt32HeadAt(pos)
 	})
-
-	w := binary.SelectWriter()
-	defer binary.PutWriter(w)
-	w.WriteUInt32(uint32(len(head)+len(body)) + 4)
-	w.Write(head)
-	w.Write(body)
-	return append([]byte(nil), w.Bytes()...) // copy
 }
 
 func (t *Transport) parse(head []byte) *Request {
diff --git a/client/tlv_decoders.go b/client/tlv_decoders.go
index a28bd9eb5..6337abf48 100644
--- a/client/tlv_decoders.go
+++ b/client/tlv_decoders.go
@@ -111,7 +111,13 @@ func (c *QQClient) decodeT119(data, ek []byte) {
 	s.PsKeyMap = psKeyMap
 	s.Pt4TokenMap = pt4TokenMap
 	if len(c.PasswordMd5[:]) > 0 {
-		key := md5.Sum(append(append(c.PasswordMd5[:], []byte{0x00, 0x00, 0x00, 0x00}...), binary.NewWriterF(func(w *binary.Writer) { w.WriteUInt32(uint32(c.Uin)) })...))
+		data, cl := binary.OpenWriterF(func(w *binary.Writer) {
+			w.Write(c.PasswordMd5[:])
+			w.WriteUInt32(0) // []byte{0x00, 0x00, 0x00, 0x00}...
+			w.WriteUInt32(uint32(c.Uin))
+		})
+		key := md5.Sum(data)
+		cl()
 		decrypted := binary.NewTeaCipher(key[:]).Decrypt(c.sig.EncryptedA1)
 		if len(decrypted) > 51+16 {
 			dr := binary.NewReader(decrypted)
diff --git a/internal/packets/global.go b/internal/packets/global.go
index cc2abf7f2..3ef09564e 100644
--- a/internal/packets/global.go
+++ b/internal/packets/global.go
@@ -31,9 +31,8 @@ type IncomingPacket struct {
 
 func BuildCode2DRequestPacket(seq uint32, j uint64, cmd uint16, bodyFunc func(writer *binary.Writer)) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
-		body := binary.NewWriterF(bodyFunc)
 		w.WriteByte(2)
-		w.WriteUInt16(uint16(43 + len(body) + 1))
+		pos := w.AllocUInt16Head()
 		w.WriteUInt16(cmd)
 		w.Write(make([]byte, 21))
 		w.WriteByte(3)
@@ -41,8 +40,9 @@ func BuildCode2DRequestPacket(seq uint32, j uint64, cmd uint16, bodyFunc func(wr
 		w.WriteUInt16(50) // version
 		w.WriteUInt32(seq)
 		w.WriteUInt64(j)
-		w.Write(body)
+		bodyFunc(w)
 		w.WriteByte(3)
+		w.WriteUInt16HeadUsingTotalBufferLenAt(pos)
 	})
 }
 
diff --git a/internal/tlv/t1.go b/internal/tlv/t1.go
index 1b5ce6b0c..e2f018099 100644
--- a/internal/tlv/t1.go
+++ b/internal/tlv/t1.go
@@ -13,13 +13,13 @@ func T1(uin uint32, ip []byte) []byte {
 	}
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x01)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteUInt16(1)
-			w.WriteUInt32(rand.Uint32())
-			w.WriteUInt32(uin)
-			w.WriteUInt32(uint32(time.Now().UnixNano() / 1e6))
-			w.Write(ip)
-			w.WriteUInt16(0)
-		}))
+		pos := w.AllocUInt16Head()
+		w.WriteUInt16(1)
+		w.WriteUInt32(rand.Uint32())
+		w.WriteUInt32(uin)
+		w.WriteUInt32(uint32(time.Now().UnixNano() / 1e6))
+		w.Write(ip)
+		w.WriteUInt16(0)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t100.go b/internal/tlv/t100.go
index 68b67f063..dc0693f2a 100644
--- a/internal/tlv/t100.go
+++ b/internal/tlv/t100.go
@@ -7,13 +7,13 @@ import (
 func T100(ssoVersion, protocol, mainSigMap uint32) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x100)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteUInt16(1)
-			w.WriteUInt32(ssoVersion)
-			w.WriteUInt32(16)
-			w.WriteUInt32(protocol)
-			w.WriteUInt32(0)          // App client version
-			w.WriteUInt32(mainSigMap) // 34869472
-		}))
+		pos := w.AllocUInt16Head()
+		w.WriteUInt16(1)
+		w.WriteUInt32(ssoVersion)
+		w.WriteUInt32(16)
+		w.WriteUInt32(protocol)
+		w.WriteUInt32(0)          // App client version
+		w.WriteUInt32(mainSigMap) // 34869472
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t106.go b/internal/tlv/t106.go
index ccd837a4c..24090b7d2 100644
--- a/internal/tlv/t106.go
+++ b/internal/tlv/t106.go
@@ -2,7 +2,6 @@ package tlv
 
 import (
 	"crypto/md5"
-	binary2 "encoding/binary"
 	"math/rand"
 	"strconv"
 	"time"
@@ -13,7 +12,19 @@ import (
 func T106(uin, salt, appId, ssoVer uint32, passwordMd5 [16]byte, guidAvailable bool, guid, tgtgtKey []byte, wtf uint32) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x106)
-		body := binary.NewWriterF(func(w *binary.Writer) {
+		pos := w.AllocUInt16Head()
+		keydata, kcl := binary.OpenWriterF(func(w *binary.Writer) {
+			w.Write(passwordMd5[:])
+			w.WriteUInt32(0) // []byte{0x00, 0x00, 0x00, 0x00}...
+			if salt != 0 {
+				w.WriteUInt32(salt)
+			} else {
+				w.WriteUInt32(uin)
+			}
+		})
+		key := md5.Sum(keydata)
+		kcl()
+		body, cl := binary.OpenWriterF(func(w *binary.Writer) {
 			w.WriteUInt16(4)
 			w.WriteUInt32(rand.Uint32())
 			w.WriteUInt32(ssoVer)
@@ -25,33 +36,27 @@ func T106(uin, salt, appId, ssoVer uint32, passwordMd5 [16]byte, guidAvailable b
 				w.WriteUInt64(uint64(uin))
 			}
 			w.WriteUInt32(uint32(time.Now().UnixNano() / 1e6))
-			w.Write([]byte{0x00, 0x00, 0x00, 0x00}) // fake ip
+			w.WriteUInt32(0) // fake ip w.Write([]byte{0x00, 0x00, 0x00, 0x00})
 			w.WriteByte(0x01)
 			w.Write(passwordMd5[:])
 			w.Write(tgtgtKey)
 			w.WriteUInt32(wtf)
 			w.WriteBool(guidAvailable)
 			if len(guid) == 0 {
-				for i := 0; i < 4; i++ {
-					w.WriteUInt32(rand.Uint32())
-				}
+				w.WriteUInt32(rand.Uint32())
+				w.WriteUInt32(rand.Uint32())
+				w.WriteUInt32(rand.Uint32())
+				w.WriteUInt32(rand.Uint32())
 			} else {
 				w.Write(guid)
 			}
 			w.WriteUInt32(appId)
 			w.WriteUInt32(1) // password login
-			w.WriteBytesShort([]byte(strconv.FormatInt(int64(uin), 10)))
+			w.WriteStringShort(strconv.FormatInt(int64(uin), 10))
 			w.WriteUInt16(0)
 		})
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			b := make([]byte, 4)
-			if salt != 0 {
-				binary2.BigEndian.PutUint32(b, salt)
-			} else {
-				binary2.BigEndian.PutUint32(b, uin)
-			}
-			key := md5.Sum(append(append(passwordMd5[:], []byte{0x00, 0x00, 0x00, 0x00}...), b...))
-			w.EncryptAndWrite(key[:], body)
-		}))
+		w.EncryptAndWrite(key[:], body)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
+		cl()
 	})
 }
diff --git a/internal/tlv/t107.go b/internal/tlv/t107.go
index 5650b9f0f..5739c5cb6 100644
--- a/internal/tlv/t107.go
+++ b/internal/tlv/t107.go
@@ -5,11 +5,11 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T107(picType uint16) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x107)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteUInt16(picType)
-			w.WriteByte(0x00)
-			w.WriteUInt16(0)
-			w.WriteByte(0x01)
-		}))
+		pos := w.AllocUInt16Head()
+		w.WriteUInt16(picType)
+		w.WriteByte(0x00)
+		w.WriteUInt16(0)
+		w.WriteByte(0x01)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t109.go b/internal/tlv/t109.go
index ff711851b..638fad4f2 100644
--- a/internal/tlv/t109.go
+++ b/internal/tlv/t109.go
@@ -9,9 +9,9 @@ import (
 func T109(androidId []byte) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x109)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			h := md5.Sum(androidId)
-			w.Write(h[:])
-		}))
+		pos := w.AllocUInt16Head()
+		h := md5.Sum(androidId)
+		w.Write(h[:])
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t116.go b/internal/tlv/t116.go
index 7e4629f71..9b70bae2d 100644
--- a/internal/tlv/t116.go
+++ b/internal/tlv/t116.go
@@ -5,12 +5,12 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T116(miscBitmap, subSigMap uint32) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x116)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteByte(0x00)
-			w.WriteUInt32(miscBitmap)
-			w.WriteUInt32(subSigMap)
-			w.WriteByte(0x01)
-			w.WriteUInt32(1600000226) // app id list
-		}))
+		pos := w.AllocUInt16Head()
+		w.WriteByte(0x00)
+		w.WriteUInt32(miscBitmap)
+		w.WriteUInt32(subSigMap)
+		w.WriteByte(0x01)
+		w.WriteUInt32(1600000226) // app id list
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t124.go b/internal/tlv/t124.go
index 7bf5479c2..21fe35f21 100644
--- a/internal/tlv/t124.go
+++ b/internal/tlv/t124.go
@@ -5,13 +5,13 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T124(osType, osVersion, simInfo, apn []byte) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x124)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteTlvLimitedSize(osType, 16)
-			w.WriteTlvLimitedSize(osVersion, 16)
-			w.WriteUInt16(2) // Network type wifi
-			w.WriteTlvLimitedSize(simInfo, 16)
-			w.WriteTlvLimitedSize([]byte{}, 16)
-			w.WriteTlvLimitedSize(apn, 16)
-		}))
+		pos := w.AllocUInt16Head()
+		w.WriteTlvLimitedSize(osType, 16)
+		w.WriteTlvLimitedSize(osVersion, 16)
+		w.WriteUInt16(2) // Network type wifi
+		w.WriteTlvLimitedSize(simInfo, 16)
+		w.WriteTlvLimitedSize([]byte{}, 16)
+		w.WriteTlvLimitedSize(apn, 16)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t128.go b/internal/tlv/t128.go
index 028123030..e24d023a9 100644
--- a/internal/tlv/t128.go
+++ b/internal/tlv/t128.go
@@ -5,15 +5,15 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T128(isGuidFromFileNull, isGuidAvailable, isGuidChanged bool, guidFlag uint32, buildModel, guid, buildBrand []byte) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x128)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteUInt16(0)
-			w.WriteBool(isGuidFromFileNull)
-			w.WriteBool(isGuidAvailable)
-			w.WriteBool(isGuidChanged)
-			w.WriteUInt32(guidFlag)
-			w.WriteTlvLimitedSize(buildModel, 32)
-			w.WriteTlvLimitedSize(guid, 16)
-			w.WriteTlvLimitedSize(buildBrand, 16)
-		}))
+		pos := w.AllocUInt16Head()
+		w.WriteUInt16(0)
+		w.WriteBool(isGuidFromFileNull)
+		w.WriteBool(isGuidAvailable)
+		w.WriteBool(isGuidChanged)
+		w.WriteUInt32(guidFlag)
+		w.WriteTlvLimitedSize(buildModel, 32)
+		w.WriteTlvLimitedSize(guid, 16)
+		w.WriteTlvLimitedSize(buildBrand, 16)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t141.go b/internal/tlv/t141.go
index 677d0add2..2d45ae9ed 100644
--- a/internal/tlv/t141.go
+++ b/internal/tlv/t141.go
@@ -5,11 +5,11 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T141(simInfo, apn []byte) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x141)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteUInt16(1)
-			w.WriteBytesShort(simInfo)
-			w.WriteUInt16(2) // network type wifi
-			w.WriteBytesShort(apn)
-		}))
+		pos := w.AllocUInt16Head()
+		w.WriteUInt16(1)
+		w.WriteBytesShort(simInfo)
+		w.WriteUInt16(2) // network type wifi
+		w.WriteBytesShort(apn)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t142.go b/internal/tlv/t142.go
index a95f273de..46752be3b 100644
--- a/internal/tlv/t142.go
+++ b/internal/tlv/t142.go
@@ -5,9 +5,9 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T142(apkId string) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x142)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteUInt16(0)
-			w.WriteTlvLimitedSize([]byte(apkId), 32)
-		}))
+		pos := w.AllocUInt16Head()
+		w.WriteUInt16(0)
+		w.WriteTlvLimitedSize([]byte(apkId), 32)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t144.go b/internal/tlv/t144.go
index 32042402c..ab014ac93 100644
--- a/internal/tlv/t144.go
+++ b/internal/tlv/t144.go
@@ -12,15 +12,15 @@ func T144(
 ) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x144)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.EncryptAndWrite(tgtgtKey, binary.NewWriterF(func(w *binary.Writer) {
-				w.WriteUInt16(5)
-				w.Write(T109(imei))
-				w.Write(T52D(devInfo))
-				w.Write(T124(osType, osVersion, simInfo, apn))
-				w.Write(T128(isGuidFromFileNull, isGuidAvailable, isGuidChanged, guidFlag, buildModel, guid, buildBrand))
-				w.Write(T16E(buildModel))
-			}))
+		pos := w.AllocUInt16Head()
+		w.EncryptAndWrite(tgtgtKey, binary.NewWriterF(func(w *binary.Writer) {
+			w.WriteUInt16(5)
+			w.Write(T109(imei))
+			w.Write(T52D(devInfo))
+			w.Write(T124(osType, osVersion, simInfo, apn))
+			w.Write(T128(isGuidFromFileNull, isGuidAvailable, isGuidChanged, guidFlag, buildModel, guid, buildBrand))
+			w.Write(T16E(buildModel))
 		}))
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t145.go b/internal/tlv/t145.go
index fd1c0f0b5..9792953f8 100644
--- a/internal/tlv/t145.go
+++ b/internal/tlv/t145.go
@@ -5,8 +5,8 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T145(guid []byte) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x145)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.Write(guid)
-		}))
+		pos := w.AllocUInt16Head()
+		w.Write(guid)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t147.go b/internal/tlv/t147.go
index f567a4dd3..4de436baa 100644
--- a/internal/tlv/t147.go
+++ b/internal/tlv/t147.go
@@ -5,10 +5,10 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T147(appId uint32, apkVersionName, apkSignatureMd5 []byte) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x147)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteUInt32(appId)
-			w.WriteTlvLimitedSize(apkVersionName, 32)
-			w.WriteTlvLimitedSize(apkSignatureMd5, 32)
-		}))
+		pos := w.AllocUInt16Head()
+		w.WriteUInt32(appId)
+		w.WriteTlvLimitedSize(apkVersionName, 32)
+		w.WriteTlvLimitedSize(apkSignatureMd5, 32)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t154.go b/internal/tlv/t154.go
index b0612c32b..142396704 100644
--- a/internal/tlv/t154.go
+++ b/internal/tlv/t154.go
@@ -5,8 +5,8 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T154(seq uint16) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x154)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteUInt32(uint32(seq))
-		}))
+		pos := w.AllocUInt16Head()
+		w.WriteUInt32(uint32(seq))
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t16.go b/internal/tlv/t16.go
index c8d94fbbc..0bd5c79cf 100644
--- a/internal/tlv/t16.go
+++ b/internal/tlv/t16.go
@@ -5,14 +5,14 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T16(ssoVersion, appId, subAppId uint32, guid, apkId, apkVersionName, apkSign []byte) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x16)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteUInt32(ssoVersion)
-			w.WriteUInt32(appId)
-			w.WriteUInt32(subAppId)
-			w.Write(guid)
-			w.WriteBytesShort(apkId)
-			w.WriteBytesShort(apkVersionName)
-			w.WriteBytesShort(apkSign)
-		}))
+		pos := w.AllocUInt16Head()
+		w.WriteUInt32(ssoVersion)
+		w.WriteUInt32(appId)
+		w.WriteUInt32(subAppId)
+		w.Write(guid)
+		w.WriteBytesShort(apkId)
+		w.WriteBytesShort(apkVersionName)
+		w.WriteBytesShort(apkSign)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t166.go b/internal/tlv/t166.go
index e64b1ddb2..d4e50f388 100644
--- a/internal/tlv/t166.go
+++ b/internal/tlv/t166.go
@@ -5,8 +5,8 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T166(imageType byte) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x166)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteByte(imageType)
-		}))
+		pos := w.AllocUInt16Head()
+		w.WriteByte(imageType)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t16e.go b/internal/tlv/t16e.go
index 4b13175e3..e0ea85895 100644
--- a/internal/tlv/t16e.go
+++ b/internal/tlv/t16e.go
@@ -5,8 +5,8 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T16E(buildModel []byte) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x16e)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.Write(buildModel)
-		}))
+		pos := w.AllocUInt16Head()
+		w.Write(buildModel)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t177.go b/internal/tlv/t177.go
index 45be3ca12..f93c72dd9 100644
--- a/internal/tlv/t177.go
+++ b/internal/tlv/t177.go
@@ -5,10 +5,10 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T177(buildTime uint32, sdkVersion string) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x177)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteByte(0x01)
-			w.WriteUInt32(buildTime)
-			w.WriteBytesShort([]byte(sdkVersion))
-		}))
+		pos := w.AllocUInt16Head()
+		w.WriteByte(0x01)
+		w.WriteUInt32(buildTime)
+		w.WriteStringShort(sdkVersion)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t17a.go b/internal/tlv/t17a.go
index eb3691f01..90b60bc2a 100644
--- a/internal/tlv/t17a.go
+++ b/internal/tlv/t17a.go
@@ -5,8 +5,8 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T17A(value int32) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x17a)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteUInt32(uint32(value))
-		}))
+		pos := w.AllocUInt16Head()
+		w.WriteUInt32(uint32(value))
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t17c.go b/internal/tlv/t17c.go
index 358c11ccc..3dfd47f12 100644
--- a/internal/tlv/t17c.go
+++ b/internal/tlv/t17c.go
@@ -5,8 +5,8 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T17C(code string) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x17c)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteStringShort(code)
-		}))
+		pos := w.AllocUInt16Head()
+		w.WriteStringShort(code)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t18.go b/internal/tlv/t18.go
index e5b6a7cc8..1b33b0304 100644
--- a/internal/tlv/t18.go
+++ b/internal/tlv/t18.go
@@ -5,14 +5,14 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T18(appId uint32, uin uint32) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x18)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteUInt16(1)
-			w.WriteUInt32(1536)
-			w.WriteUInt32(appId)
-			w.WriteUInt32(0)
-			w.WriteUInt32(uin)
-			w.WriteUInt16(0)
-			w.WriteUInt16(0)
-		}))
+		pos := w.AllocUInt16Head()
+		w.WriteUInt16(1)
+		w.WriteUInt32(1536)
+		w.WriteUInt32(appId)
+		w.WriteUInt32(0)
+		w.WriteUInt32(uin)
+		w.WriteUInt16(0)
+		w.WriteUInt16(0)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t187.go b/internal/tlv/t187.go
index 500f619e4..de65fe7fb 100644
--- a/internal/tlv/t187.go
+++ b/internal/tlv/t187.go
@@ -9,9 +9,9 @@ import (
 func T187(macAddress []byte) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x187)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			h := md5.Sum(macAddress)
-			w.Write(h[:])
-		}))
+		pos := w.AllocUInt16Head()
+		h := md5.Sum(macAddress)
+		w.Write(h[:])
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t188.go b/internal/tlv/t188.go
index 9731ca4e9..6ddb87961 100644
--- a/internal/tlv/t188.go
+++ b/internal/tlv/t188.go
@@ -9,9 +9,9 @@ import (
 func T188(androidId []byte) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x188)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			h := md5.Sum(androidId)
-			w.Write(h[:])
-		}))
+		pos := w.AllocUInt16Head()
+		h := md5.Sum(androidId)
+		w.Write(h[:])
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t191.go b/internal/tlv/t191.go
index 2b57e79b2..a96aff1dc 100644
--- a/internal/tlv/t191.go
+++ b/internal/tlv/t191.go
@@ -5,8 +5,8 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T191(k byte) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x191)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteByte(k)
-		}))
+		pos := w.AllocUInt16Head()
+		w.WriteByte(k)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t193.go b/internal/tlv/t193.go
index e81928858..96ca0bcf1 100644
--- a/internal/tlv/t193.go
+++ b/internal/tlv/t193.go
@@ -5,8 +5,8 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T193(ticket string) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x193)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.Write([]byte(ticket))
-		}))
+		pos := w.AllocUInt16Head()
+		w.Write([]byte(ticket))
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t194.go b/internal/tlv/t194.go
index 3fb4f3337..79318eaeb 100644
--- a/internal/tlv/t194.go
+++ b/internal/tlv/t194.go
@@ -5,8 +5,8 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T194(imsiMd5 []byte) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x194)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.Write(imsiMd5)
-		}))
+		pos := w.AllocUInt16Head()
+		w.Write(imsiMd5)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t197.go b/internal/tlv/t197.go
index 6af17954c..6a8b402f1 100644
--- a/internal/tlv/t197.go
+++ b/internal/tlv/t197.go
@@ -5,6 +5,6 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T197() []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x197)
-		w.WriteBytesShort([]byte{0})
+		w.Write([]byte{0, 1, 0}) // w.WriteBytesShort([]byte{0})
 	})
 }
diff --git a/internal/tlv/t198.go b/internal/tlv/t198.go
index 3317be6d5..6dcc9b48d 100644
--- a/internal/tlv/t198.go
+++ b/internal/tlv/t198.go
@@ -5,6 +5,6 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T198() []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x198)
-		w.WriteBytesShort([]byte{0})
+		w.Write([]byte{0, 1, 0}) // w.WriteBytesShort([]byte{0})
 	})
 }
diff --git a/internal/tlv/t1b.go b/internal/tlv/t1b.go
index fad8c159f..f6b30f70c 100644
--- a/internal/tlv/t1b.go
+++ b/internal/tlv/t1b.go
@@ -5,15 +5,15 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T1B(micro, version, size, margin, dpi, ecLevel, hint uint32) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x1B)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteUInt32(micro)
-			w.WriteUInt32(version)
-			w.WriteUInt32(size)
-			w.WriteUInt32(margin)
-			w.WriteUInt32(dpi)
-			w.WriteUInt32(ecLevel)
-			w.WriteUInt32(hint)
-			w.WriteUInt16(0)
-		}))
+		pos := w.AllocUInt16Head()
+		w.WriteUInt32(micro)
+		w.WriteUInt32(version)
+		w.WriteUInt32(size)
+		w.WriteUInt32(margin)
+		w.WriteUInt32(dpi)
+		w.WriteUInt32(ecLevel)
+		w.WriteUInt32(hint)
+		w.WriteUInt16(0)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t1d.go b/internal/tlv/t1d.go
index 58996978c..099b31e52 100644
--- a/internal/tlv/t1d.go
+++ b/internal/tlv/t1d.go
@@ -5,12 +5,12 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T1D(miscBitmap uint32) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x1D)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteByte(1)
-			w.WriteUInt32(miscBitmap)
-			w.WriteUInt32(0)
-			w.WriteByte(0)
-			w.WriteUInt32(0)
-		}))
+		pos := w.AllocUInt16Head()
+		w.WriteByte(1)
+		w.WriteUInt32(miscBitmap)
+		w.WriteUInt32(0)
+		w.WriteByte(0)
+		w.WriteUInt32(0)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t1f.go b/internal/tlv/t1f.go
index 2d7b83654..4e671d84a 100644
--- a/internal/tlv/t1f.go
+++ b/internal/tlv/t1f.go
@@ -5,20 +5,14 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T1F(isRoot bool, osName, osVersion, simOperatorName, apn []byte, networkType uint16) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x1F)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteByte(func() byte {
-				if isRoot {
-					return 1
-				} else {
-					return 0
-				}
-			}())
-			w.WriteBytesShort(osName)
-			w.WriteBytesShort(osVersion)
-			w.WriteUInt16(networkType)
-			w.WriteBytesShort(simOperatorName)
-			w.WriteBytesShort([]byte{})
-			w.WriteBytesShort(apn)
-		}))
+		pos := w.AllocUInt16Head()
+		w.WriteBool(isRoot)
+		w.WriteBytesShort(osName)
+		w.WriteBytesShort(osVersion)
+		w.WriteUInt16(networkType)
+		w.WriteBytesShort(simOperatorName)
+		w.WriteUInt16(0) // w.WriteBytesShort([]byte{})
+		w.WriteBytesShort(apn)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t2.go b/internal/tlv/t2.go
index 2f0656c4b..efa2037a4 100644
--- a/internal/tlv/t2.go
+++ b/internal/tlv/t2.go
@@ -5,10 +5,10 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T2(result string, sign []byte) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x02)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteUInt16(0)
-			w.WriteStringShort(result)
-			w.WriteBytesShort(sign)
-		}))
+		pos := w.AllocUInt16Head()
+		w.WriteUInt16(0)
+		w.WriteStringShort(result)
+		w.WriteBytesShort(sign)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t202.go b/internal/tlv/t202.go
index e694547ce..ec1c4f69d 100644
--- a/internal/tlv/t202.go
+++ b/internal/tlv/t202.go
@@ -5,9 +5,9 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T202(wifiBSSID, wifiSSID []byte) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x202)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteTlvLimitedSize(wifiBSSID, 16)
-			w.WriteTlvLimitedSize(wifiSSID, 32)
-		}))
+		pos := w.AllocUInt16Head()
+		w.WriteTlvLimitedSize(wifiBSSID, 16)
+		w.WriteTlvLimitedSize(wifiSSID, 32)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t35.go b/internal/tlv/t35.go
index 4fc008513..9903096df 100644
--- a/internal/tlv/t35.go
+++ b/internal/tlv/t35.go
@@ -5,8 +5,8 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T35(productType uint32) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x35)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteUInt32(productType)
-		}))
+		pos := w.AllocUInt16Head()
+		w.WriteUInt32(productType)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t400.go b/internal/tlv/t400.go
index 9a22344e6..59173f17a 100644
--- a/internal/tlv/t400.go
+++ b/internal/tlv/t400.go
@@ -9,17 +9,17 @@ import (
 func T400(g []byte, uin int64, guid, dpwd []byte, j2, j3 int64, randSeed []byte) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x400)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.EncryptAndWrite(g, binary.NewWriterF(func(w *binary.Writer) {
-				w.WriteUInt16(1) // version
-				w.WriteUInt64(uint64(uin))
-				w.Write(guid)
-				w.Write(dpwd)
-				w.WriteUInt32(uint32(j2))
-				w.WriteUInt32(uint32(j3))
-				w.WriteUInt32(uint32(time.Now().Unix()))
-				w.Write(randSeed)
-			}))
+		pos := w.AllocUInt16Head()
+		w.EncryptAndWrite(g, binary.NewWriterF(func(w *binary.Writer) {
+			w.WriteUInt16(1) // version
+			w.WriteUInt64(uint64(uin))
+			w.Write(guid)
+			w.Write(dpwd)
+			w.WriteUInt32(uint32(j2))
+			w.WriteUInt32(uint32(j3))
+			w.WriteUInt32(uint32(time.Now().Unix()))
+			w.Write(randSeed)
 		}))
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t511.go b/internal/tlv/t511.go
index 72af0999b..43609e75e 100644
--- a/internal/tlv/t511.go
+++ b/internal/tlv/t511.go
@@ -1,53 +1,64 @@
 package tlv
 
 import (
-	"strconv"
-	"strings"
-
 	"github.com/Mrs4s/MiraiGo/binary"
 )
 
 func T511(domains []string) []byte {
-	var arr2 []string
-	for _, d := range domains {
-		if d != "" {
-			arr2 = append(arr2, d)
+	nonnildomains := domains
+	// 目前的所有调用均无 ""
+	/*
+		hasnil := false
+		for _, d := range domains {
+			if d == "" {
+				hasnil = true
+				break
+			}
+		}
+		if hasnil {
+			nonnildomains = nonnildomains[:0]
+			for _, d := range domains {
+				if d != "" {
+					nonnildomains = append(nonnildomains, d)
+				}
+			}
 		}
-	}
+	*/
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x511)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteUInt16(uint16(len(arr2)))
-			for _, d := range arr2 {
-				indexOf := strings.Index(d, "(")
-				indexOf2 := strings.Index(d, ")")
-				if indexOf != 0 || indexOf2 <= 0 {
-					w.WriteByte(0x01)
-					w.WriteBytesShort([]byte(d))
-				} else {
-					var b byte
-					var z bool
-					i, err := strconv.Atoi(d[indexOf+1 : indexOf2])
-					if err == nil {
-						z2 := (1048576 & i) > 0
-						if (i & 134217728) > 0 {
-							z = true
-						} else {
-							z = false
-						}
-						if z2 {
-							b = 1
-						} else {
-							b = 0
-						}
-						if z {
-							b |= 2
-						}
-						w.WriteByte(b)
-						w.WriteBytesShort([]byte(d[indexOf2+1:]))
+		pos := w.AllocUInt16Head()
+		w.WriteUInt16(uint16(len(nonnildomains)))
+		for _, d := range nonnildomains {
+			// 目前的所有调用均不会出现 ()
+			// indexOf := strings.Index(d, "(")
+			// indexOf2 := strings.Index(d, ")")
+			// if indexOf != 0 || indexOf2 <= 0 {
+			w.WriteByte(0x01)
+			w.WriteStringShort(d)
+			/* } else {
+				var b byte
+				var z bool
+				i, err := strconv.Atoi(d[indexOf+1 : indexOf2])
+				if err == nil {
+					z2 := (1048576 & i) > 0
+					if (i & 134217728) > 0 {
+						z = true
+					} else {
+						z = false
 					}
+					if z2 {
+						b = 1
+					} else {
+						b = 0
+					}
+					if z {
+						b |= 2
+					}
+					w.WriteByte(b)
+					w.WriteBytesShort([]byte(d[indexOf2+1:]))
 				}
-			}
-		}))
+			}*/
+		}
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t516.go b/internal/tlv/t516.go
index 6a64c95e7..fbc2119e3 100644
--- a/internal/tlv/t516.go
+++ b/internal/tlv/t516.go
@@ -5,8 +5,8 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T516() []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x516)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteUInt32(0)
-		}))
+		pos := w.AllocUInt16Head()
+		w.WriteUInt32(0)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t521.go b/internal/tlv/t521.go
index 11ead58e7..9ae32d2af 100644
--- a/internal/tlv/t521.go
+++ b/internal/tlv/t521.go
@@ -5,9 +5,9 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T521(i uint32) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x521)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteUInt32(i)
-			w.WriteUInt16(0)
-		}))
+		pos := w.AllocUInt16Head()
+		w.WriteUInt32(i)
+		w.WriteUInt16(0)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t525.go b/internal/tlv/t525.go
index fe89877ad..0b843f0a3 100644
--- a/internal/tlv/t525.go
+++ b/internal/tlv/t525.go
@@ -5,9 +5,9 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T525(t536 []byte) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x525)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteUInt16(1)
-			w.Write(t536)
-		}))
+		pos := w.AllocUInt16Head()
+		w.WriteUInt16(1)
+		w.Write(t536)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t52d.go b/internal/tlv/t52d.go
index a98f79948..16273e8f1 100644
--- a/internal/tlv/t52d.go
+++ b/internal/tlv/t52d.go
@@ -5,8 +5,8 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T52D(devInfo []byte) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x52d)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.Write(devInfo)
-		}))
+		pos := w.AllocUInt16Head()
+		w.Write(devInfo)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t536.go b/internal/tlv/t536.go
index 9e23059ea..c6f5f2908 100644
--- a/internal/tlv/t536.go
+++ b/internal/tlv/t536.go
@@ -5,8 +5,8 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T536(loginExtraData []byte) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x536)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.Write(loginExtraData)
-		}))
+		pos := w.AllocUInt16Head()
+		w.Write(loginExtraData)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }
diff --git a/internal/tlv/t8.go b/internal/tlv/t8.go
index 8a7ba34aa..b2b793377 100644
--- a/internal/tlv/t8.go
+++ b/internal/tlv/t8.go
@@ -5,10 +5,10 @@ import "github.com/Mrs4s/MiraiGo/binary"
 func T8(localId uint32) []byte {
 	return binary.NewWriterF(func(w *binary.Writer) {
 		w.WriteUInt16(0x8)
-		w.WriteBytesShort(binary.NewWriterF(func(w *binary.Writer) {
-			w.WriteUInt16(0)
-			w.WriteUInt32(localId)
-			w.WriteUInt16(0)
-		}))
+		pos := w.AllocUInt16Head()
+		w.WriteUInt16(0)
+		w.WriteUInt32(localId)
+		w.WriteUInt16(0)
+		w.WriteUInt16HeadExcludeSelfAt(pos)
 	})
 }