Originally Posted by gregbradley
flashing FTF files will not affect the SIM lock status of a phone.
It will neither lock an unlocked one nor will it unlock a locked one.
i flashed the firmware of Rogers for my unlocked xperia z1 C6906, which was Branded Firmware. my phone was working fine with all sim cards. but few days ago i put the sim card of rogers, the phone automatically restart and also install some rogers network apps in phone menu. after that when i put other sim card, the network unlock code dialogue box appears. it means that phone got locked with rogers now. the rogers technicians said me if you flashed rogers branded firmware, then if you ever put rogers sim card in it, then device will locked to rogers even if its unlocked from sony.