diff --git a/bytesconv.go b/bytesconv.go
index 81f8e5b167..d54e77f933 100644
--- a/bytesconv.go
+++ b/bytesconv.go
@@ -380,7 +380,7 @@ func appendQuotedPath(dst, src []byte) []byte {
 
 	for _, c := range src {
 		if quotedPathShouldEscapeTable[int(c)] != 0 {
-			dst = append(dst, '%', upperhex[c>>4], upperhex[c&15])
+			dst = append(dst, '%', upperhex[c>>4], upperhex[c&0xf])
 		} else {
 			dst = append(dst, c)
 		}
diff --git a/header.go b/header.go
index 4cbe9f3832..fb6f0054d0 100644
--- a/header.go
+++ b/header.go
@@ -746,7 +746,7 @@ func (h *ResponseHeader) CopyTo(dst *ResponseHeader) {
 	dst.noDefaultDate = h.noDefaultDate
 
 	dst.statusCode = h.statusCode
-	dst.statusLine = append(dst.statusLine[:0], h.statusLine...)
+	dst.statusLine = append(dst.statusLine, h.statusLine...)
 	dst.contentLength = h.contentLength
 	dst.contentLengthBytes = append(dst.contentLengthBytes, h.contentLengthBytes...)
 	dst.contentType = append(dst.contentType, h.contentType...)