diff --git a/common/tls/utls_client.go b/common/tls/utls_client.go
index b3b91970..6df1a561 100644
--- a/common/tls/utls_client.go
+++ b/common/tls/utls_client.go
@@ -146,6 +146,8 @@ func newUTLSClient(router adapter.Router, serverAddress string, options option.O
 		id = utls.HelloAndroid_11_OkHttp
 	case "random":
 		id = utls.HelloRandomized
+	default:
+		return nil, E.New("unknown uTLS fingerprint: ", options.UTLS.Fingerprint)
 	}
 	return &utlsClientConfig{&tlsConfig, id}, nil
 }
diff --git a/go.mod b/go.mod
index 5a407967..5a169660 100644
--- a/go.mod
+++ b/go.mod
@@ -23,7 +23,7 @@ require (
 	github.com/pires/go-proxyproto v0.6.2
 	github.com/refraction-networking/utls v1.1.2
 	github.com/sagernet/quic-go v0.0.0-20220818150011-de611ab3e2bb
-	github.com/sagernet/sing v0.0.0-20221006081821-c4e9bf11fa00
+	github.com/sagernet/sing v0.0.0-20221008120626-60a9910eefe4
 	github.com/sagernet/sing-dns v0.0.0-20220929010544-ee843807aae3
 	github.com/sagernet/sing-shadowsocks v0.0.0-20220819002358-7461bb09a8f6
 	github.com/sagernet/sing-tun v0.0.0-20221005115555-9a556307f6a3
diff --git a/go.sum b/go.sum
index 80c39b64..8af90292 100644
--- a/go.sum
+++ b/go.sum
@@ -145,8 +145,8 @@ github.com/sagernet/quic-go v0.0.0-20220818150011-de611ab3e2bb h1:wc0yQ+SBn4TaTY
 github.com/sagernet/quic-go v0.0.0-20220818150011-de611ab3e2bb/go.mod h1:MIccjRKnPTjWwAOpl+AUGWOkzyTd9tERytudxu+1ra4=
 github.com/sagernet/sing v0.0.0-20220812082120-05f9836bff8f/go.mod h1:QVsS5L/ZA2Q5UhQwLrn0Trw+msNd/NPGEhBKR/ioWiY=
 github.com/sagernet/sing v0.0.0-20220817130738-ce854cda8522/go.mod h1:QVsS5L/ZA2Q5UhQwLrn0Trw+msNd/NPGEhBKR/ioWiY=
-github.com/sagernet/sing v0.0.0-20221006081821-c4e9bf11fa00 h1:UkgEDnH3L9eBxob+3AbE9wM4mjFnRLnaPjfLSNe+C74=
-github.com/sagernet/sing v0.0.0-20221006081821-c4e9bf11fa00/go.mod h1:zvgDYKI+vCAW9RyfyrKTgleI+DOa8lzHMPC7VZo3OL4=
+github.com/sagernet/sing v0.0.0-20221008120626-60a9910eefe4 h1:LO7xMvMGhYmjQg2vjhTzsODyzs9/WLYu5Per+/8jIeo=
+github.com/sagernet/sing v0.0.0-20221008120626-60a9910eefe4/go.mod h1:zvgDYKI+vCAW9RyfyrKTgleI+DOa8lzHMPC7VZo3OL4=
 github.com/sagernet/sing-dns v0.0.0-20220929010544-ee843807aae3 h1:AEdyJxEDFq38z0pBX/0MpikQapGMIch+1ADe9k1bJqU=
 github.com/sagernet/sing-dns v0.0.0-20220929010544-ee843807aae3/go.mod h1:SrvWLfOSlnFmH32CWXicfilAGgIXR0VjrH6yRbuXYww=
 github.com/sagernet/sing-shadowsocks v0.0.0-20220819002358-7461bb09a8f6 h1:JJfDeYYhWunvtxsU/mOVNTmFQmnzGx9dY034qG6G3g4=
diff --git a/transport/v2raywebsocket/conn.go b/transport/v2raywebsocket/conn.go
index c0d0770e..e050e2f2 100644
--- a/transport/v2raywebsocket/conn.go
+++ b/transport/v2raywebsocket/conn.go
@@ -10,6 +10,7 @@ import (
 	"time"
 
 	C "github.com/sagernet/sing-box/constant"
+	"github.com/sagernet/sing/common"
 	"github.com/sagernet/sing/common/buf"
 	E "github.com/sagernet/sing/common/exceptions"
 	"github.com/sagernet/websocket"
@@ -68,8 +69,12 @@ func (c *WebsocketConn) SetDeadline(t time.Time) error {
 	return os.ErrInvalid
 }
 
-func (c *WebsocketConn) FrontHeadroom() int {
-	return frontHeadroom
+func (c *WebsocketConn) Upstream() any {
+	return c.Conn.NetConn()
+}
+
+func (c *WebsocketConn) UpstreamWriter() any {
+	return c.Writer
 }
 
 type EarlyWebsocketConn struct {
@@ -210,8 +215,12 @@ func (c *EarlyWebsocketConn) SetWriteDeadline(t time.Time) error {
 	return c.conn.SetWriteDeadline(t)
 }
 
-func (c *EarlyWebsocketConn) FrontHeadroom() int {
-	return frontHeadroom
+func (c *EarlyWebsocketConn) Upstream() any {
+	return common.PtrOrNil(c.conn)
+}
+
+func (c *EarlyWebsocketConn) LazyHeadroom() bool {
+	return c.conn == nil
 }
 
 func wrapError(err error) error {
diff --git a/transport/v2raywebsocket/writer.go b/transport/v2raywebsocket/writer.go
index 0d2d45ac..fbb61f0f 100644
--- a/transport/v2raywebsocket/writer.go
+++ b/transport/v2raywebsocket/writer.go
@@ -10,8 +10,6 @@ import (
 	"github.com/sagernet/websocket"
 )
 
-const frontHeadroom = 14
-
 type Writer struct {
 	*websocket.Conn
 	writer   N.ExtendedWriter
@@ -85,5 +83,5 @@ func (w *Writer) Upstream() any {
 }
 
 func (w *Writer) FrontHeadroom() int {
-	return frontHeadroom
+	return 14
 }