1-Some time ago my brother bought an unlocked Galaxy S Advance I9070 and today he gave it to me, It has the stock ROM of the carrier 'Claro' (And all the bloatware ), my SIM is from another carrier (Personal) and I can use it without problems (Both carriers are from Argentina), but I've noticed something:
The phone came as new, with the box and all the accesories inside, I checked the IMEI and I found out this:
The sticker on the box and inside the phone (behind the battery) shows XXXXXX05XXXXXX3, and when i type *#06# in the phone, it shows XXXXXX99XXXXXX6 (The IMEIs are the same, except for those three numbers)
I think that when they unlocked the phone, that part of the IMEI changed (As far as I know the IMEI shouldn't/mustn't change).Am I right? Would I have any problems with that?
2-The stock ROM of the aftermentioned phone has Gingerbread 2.3.6 and I'd like to install KitKat or Jellybean. Will the phone lock again? (I'm almost sure that it was soft-unlocked or something like that) Do I have to backup the efs partition to keep the IMEI and the phone unlocked?
When my brother bought it, the phone had the Superuser app installed, he did a factory reset (I don't know why.. ) and (as expected) the app dissappeared. I reinstalled it again today but it looks like the phone lost the root (When trying root apps like root explorer i get the pop up asking for root authorization, when I hit "allow" nothing happens... Also, if I type "su" in terminal it doesn't show the #, it keeps there waiting for more commands)
If you need more information I'll gladly provide it
Thanks in advance