diff --git a/server_test.go b/server_test.go
index 727306b..01c832f 100644
--- a/server_test.go
+++ b/server_test.go
@@ -59,6 +59,7 @@ func TestRequestCtxRedirect(t *testing.T) {
 	testRequestCtxRedirect(t, "http://qqq/foo/bar?baz=111", "./.././../x.html", "http://qqq/x.html")
 	testRequestCtxRedirect(t, "http://qqq/foo/bar?baz=111", "http://foo.bar/baz", "http://foo.bar/baz")
 	testRequestCtxRedirect(t, "http://qqq/foo/bar?baz=111", "https://foo.bar/baz", "https://foo.bar/baz")
+	testRequestCtxRedirect(t, "https://foo.com/bar?aaa", "//google.com/aaa?bb", "https://google.com/aaa?bb")
 }
 
 func testRequestCtxRedirect(t *testing.T, origURL, redirectURL, expectedURL string) {
diff --git a/uri.go b/uri.go
index 48a445e..43060de 100644
--- a/uri.go
+++ b/uri.go
@@ -395,6 +395,22 @@ func (u *URI) updateBytes(newURI, buf []byte) []byte {
 	if len(newURI) == 0 {
 		return buf
 	}
+
+	n := bytes.Index(newURI, strSlashSlash)
+	if n >= 0 {
+		// absolute uri
+		var b [32]byte
+		schemeOriginal := b[:0]
+		if len(u.scheme) > 0 {
+			schemeOriginal = append([]byte(nil), u.scheme...)
+		}
+		u.Parse(nil, newURI)
+		if len(schemeOriginal) > 0 && len(u.scheme) == 0 {
+			u.scheme = append(u.scheme[:0], schemeOriginal...)
+		}
+		return buf
+	}
+
 	if newURI[0] == '/' {
 		// uri without host
 		buf = u.appendSchemeHost(buf[:0])
@@ -403,13 +419,6 @@ func (u *URI) updateBytes(newURI, buf []byte) []byte {
 		return buf
 	}
 
-	n := bytes.Index(newURI, strColonSlashSlash)
-	if n >= 0 {
-		// absolute uri
-		u.Parse(nil, newURI)
-		return buf
-	}
-
 	// relative path
 	switch newURI[0] {
 	case '?':
@@ -467,7 +476,7 @@ func (u *URI) String() string {
 }
 
 func splitHostURI(host, uri []byte) ([]byte, []byte, []byte) {
-	n := bytes.Index(uri, strColonSlashSlash)
+	n := bytes.Index(uri, strSlashSlash)
 	if n < 0 {
 		return strHTTP, host, uri
 	}
@@ -475,7 +484,10 @@ func splitHostURI(host, uri []byte) ([]byte, []byte, []byte) {
 	if bytes.IndexByte(scheme, '/') >= 0 {
 		return strHTTP, host, uri
 	}
-	n += len(strColonSlashSlash)
+	if len(scheme) > 0 && scheme[len(scheme)-1] == ':' {
+		scheme = scheme[:len(scheme)-1]
+	}
+	n += len(strSlashSlash)
 	uri = uri[n:]
 	n = bytes.IndexByte(uri, '/')
 	if n < 0 {
diff --git a/uri_test.go b/uri_test.go
index 508a9ba..b86bb48 100644
--- a/uri_test.go
+++ b/uri_test.go
@@ -112,6 +112,9 @@ func TestURIUpdate(t *testing.T) {
 
 	// hash
 	testURIUpdate(t, "http://foo.bar/baz#aaa", "#fragment", "http://foo.bar/baz#fragment")
+
+	// uri without scheme
+	testURIUpdate(t, "https://foo.bar/baz", "//aaa.bbb/cc?dd", "https://aaa.bbb/cc?dd")
 }
 
 func testURIUpdate(t *testing.T, base, update, result string) {