[ROM] [MT6575] Porting Help, everything works exept 3G

[alifax89]

Hello everyone, just a little introduction, I have a fake lenovo phone (the sold me saying that was original) but the stock rom it's really slow and it draws a lot of battery so I just started to install roms to make it a little better... Now, I've found a rom that works great, it's an original lenovo rom everything works, both sims recognized, audio, wifi, gps, just one thing do not work... 3G!
The phone has 3G and in the stock ROM works great, I've tried some methods that I found on some forums for example

Replace from /etc folder, mddb then replace agps_profiles_conf, apns-conf,epo_conf, spn-conf, virtual-spn-conf-by-efpnn, virtual-spn-conf-by-efspn, virtual-spn-conf-by-imsi

But do not work, I don't know what is the problem and what file I need to replace to make it work!
Do you have any suggestion?
P.S. In the settings I can set to use 3G and GPRS, Only 3G or Only GPRS, if I set only 3g it says no-signal, but I'm sure at 1000% that there is 3G!
Please help a lost soul!

[DerDat]

did you check in mtk engineering mode (mobile uncle app can access it) to see what umts frequencies are listed there? it's probably something to do with modem.img or baseband files.

[WuddaWaste]

When you had the original ROM on the phone, did it get 3G?
If it did, did you verify the speeds were truly 3G and that it wasn't being faked?
If it didn't, there's a probability that the phone doesn't have the proper hardware for 3G in your area.

@DerDat 's suggestion to check in MTK Engineering Mode is definitely a step in the right direction either way.