Mifi 2200 Questions

[wepro]

Hello guys. I have recently learned to flash the mifi 2200 using the android method. So far, the internet is working flawlesly. However, I have some questions I would really appreciate it if someone would share their knowledge about the following things:

.dmi file for mifi 2200. What is it? How do you use it?
.nvt file for mifi 2200 Is this the generic firmware we have to flash to debrand mifi 2200?
.nvi_db ??

Looking for info about debranding the mifi 2200 I have come across those files and some .exe files too but I really don't know how to use them yet.

Thanks