Flash Stock FTF via Flashtool in Flashmode. You can use also PC Companion to repire your phone but with Unlocked Bootloader I don't know if it will work.
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My Evolution: Sony Xperia Z1 - UB + 4.3 Rooted + Deodexed, HTC HD2, HTC Diamond 2, HTC HD Blackstone, Nokia 7070 Prism, Qtek 9100, Nokia 3100, Motorola T720i, Nokia 3310, Sony Ericson PF 768 (Blue)

How Get Root on Sony Xperia Z1 with Locked Bootloader and the Latest Android 4.4