In cases where a "wrong" update or a power failure during an update "bricks" the unit (leaving it stuck in a power-cycling loop), standard resets often fail. LTE-Forum Österreich The Solution: Enthusiasts on forums like LTEForum.at have developed methods to put the unit into EDL (Emergency Download) Mode
Note: Downgrading will factory reset your device. You must reconfigure your APN settings afterward. Zte Mc888 Firmware Fix