Use male to male USB cable, connect to USB port on router and your PC. (Must be a windows pc) then load that marvel unlock software(Google marvel mifi unlocker tool) some YouTube videos or links to download it will come up. Follow the process, and fill in all the numbers required.
(I used Google translate to know what to fill in cause the app is in Chinese) .
When you are done reboot and the router will be unlocked but work 3G networks only no LTE