revert back to older OS version

[AC Question]

My T-Mobile LG G4 H411 was working fine android version 5.0. I have updated it to Android version 6.0. Now it is factory locked. How can I revert back to older OS version or/and unlock my phone on 6.0 marshmellow?

 

[belodion]

Are you saying that the update caused the phone to revert to a former state of being locked to another carrier?

 

[fahimalavi]

Yes belodion

 

[belodion]

Yes belodion

Okay. I was thinking that it may have been unofficially and/or incompletely network-unlocked at some time in the past, the later update causing the reversion. I believe that that happens with iPhones, and it may be the case with Android devices. The fix would presumably be to seek an official unlock from the carrier to which it has become locked.