I try to upgrade my phone from Chinese Version to International version and in some point i ended up with a bricked phone .
The only solution that worked for me was: to boot up pressing the power button and “+” button. If it is power up then connect it to your pc. You must see a recovery drive. if not you need to install windows drivers for your phone. Then copy inside this drive THE VERY FIRST FIRMWARE that you phone was running before any upgrade. This was the only solution that worked for me and i try everythink else. Hope best luck.