Hello guys, I need a quick help. My friend sent me a GS4(i377M) all the way from Canada. As it was locked, I made it unlocked in a local store by paying 2000 bucks(it wasn't cheap). It runs on a 4.3 version now(mentioned in about phone). I want to update it to stock kitkat without re-locking the phone. I don't know what he did or how he unlocked the phone. When I got the phone from him, it was rooted. That's all I know about the unlocking. I've got a little experience in backing up and flashing(experimented on my old Atrix2). So what I want to know now is whether there is a way to update my SGH I377M to stock kitkat without messing it up by re-locking the SIM again!!! if there is a way, please help me out in doing it. if there is not, can I unlock it myself after flashing it with kitkat and HOW ???