TP-Link TL-MR6400v1 lost admin password for LTE Module

Hello.
I using tp-link with openwrt firmware.
I have a problem with access to TP-LINK LTE modem via web page.
I can reach this page using 192.168.0.1 but i don't know the password.
If anybody know how to reset this password?
I reset my router twice but without success. I know that there is android inside and it have independent www page. I tryed admin/admin and username/password, but it's still wrong.