Hello I recently update mi Xiaomi MI4s to a latest unnoficial rom (v7.5.4) and sometimes, walking in the city, driving in my car, etc, my phone looses the signal without noticing the lost of 4g/3G on the top of the screen. For example when i face tunnels, underground places, etc, and then open places with signal, phone doesn't recover the data signal again. 4G is showing on the top of the screen, but it can't connect to any service, including: Whatsapp, browser, etc. It seems, it looses the "capability" of connection because of the rom or modem...i don't know! In that case, i must turn on/off flight mode and then signal comes back. My history changing roms on my Mi4s: At the beggining, i'd install v7.2.5 with unlocked bootloader -> Then, install V7.5.3 with TWRP. -> Then, V8 6.7.14 with TWRP (i didn't like this beta rom, so i back to a chinese original ROM because of locked bootloader) -> Then get back to V7.5.3 with TWRP and -> Lastly to V7.5.4 (until now). About Modems (basebands): I'd Test all modems on V7.5.4 and all has worked as the same manner. 4 months ago, with other Mi4s (white color this time), i installed V7.2.5 and then V7.5.3. Nothing other change of rom. This phone never had this problem... Could the problem be the installation of V8 and then V7 on my phone??? I attach pictures of my software and configuration if you can help me. Thank you in advance!!