diff --git a/cores/esp8266/timehelper.cpp b/cores/esp8266/timehelper.cpp
index 235bfd0a49..7e57af1d04 100644
--- a/cores/esp8266/timehelper.cpp
+++ b/cores/esp8266/timehelper.cpp
@@ -1,3 +1,21 @@
+/*
+ * timehelper.c - generic time functions
+ * Copyright (c) 2021 esp8266/Arduino. All rights reserved.
+ * This file is part of the esp8266 core for Arduino environment.
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU Lesser General Public License for more details.
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ */
+
 
 #include "Arduino.h"