diff --git a/sun/web/builder.go b/sun/web/builder.go
index d61f625..e15191b 100644
--- a/sun/web/builder.go
+++ b/sun/web/builder.go
@@ -195,6 +195,7 @@ func zipBin(confData, binPath, binName string) ([]byte, error) {
 	if err != nil {
 		return nil, err
 	}
+	bheader.Method = zip.Deflate
 	binw, err := zipw.CreateHeader(bheader)
 	if err != nil {
 		return nil, err