说明：  升级前注意事项： 1、用SD卡升级过程中严禁断电，否则会导致机器数据丢失，无法修复； 2、请在升级前将重要文件备份，以防升级后造成文件丢失；
(Note: 1, with the SD card upgrade process is strictly prohibited power outages before upgrading, otherwise it will result in the machine data loss, can not be repaired , up critical files before upgrading, in case the upgrade result in lost files )