ksa device with indian rom for now
I did manually updated my device to 4.3 ueml4 latest via mobile odin first time ... I encountered the missing signal problem and wifi not working problem too !
what I did ? silly me ... I flashed ml4 again via pc odin
now my bootloader is new and cant be downgraded
also I have knox counter and knox programs too
I cant root my device and if I do it I will loose warrenty !
I would recommend you to stay put against 4.3 update and maybe go for 4.4 kitkat when released
many missing features on 4.3 ... music player cant share music anymore ... also battery is the same but exchange services ( push mod ) is taking a big hit on my battery so I stopped it and used to check every hour option
but after flashing ml4 modem sometimes I see 3g faster than 4.1.2 and sometimes the signal dissapears
hope this helps
if anyone knows how to root this ml4 firmware without loosing warrenty please tell me
I already tried the script method and some other methed too but failed