Commands listed in this post are useful in troubleshooting of your Xexun TK102 GPS tracker, but are often omitted in official documentation. And many users of this tracker may not be aware of them.
As mentioned in this article, you can use
FORMAT command (without following it with current password) to completely wipe-out all tracker settings and reset it to factory defaults (with default password set to
123456). Read entire article for information about alternatives to this command, that have to be used to reset some clones of Xexun TK102.
Why you can reset entire device without knowing a master password is a great mystery for me. It is an obvious security leak. Knowing this and knowing your device's SIM card number, someone can do really bad things to you. But, on the other hand, it is the only way to regain control over device, if you actually forget your master password. And also the only way to act, if someone takes over your device and changes master password to one, that you don't know.
VERSIONpassword (with current master password and without space in between) to obtain currently installed firmware version. Xexun TK102 and most clones should reply with something like
JEO 2010-7-1, which seems to be firmware codename and installation date or something similar.