Download the global ROM from either of the links above (be careful to select the right region/firmware) and copy it to the root of your phone storage. That is, /SDcard/
On your phone, go to ‘Settings’ – ‘System update‘, click the ‘Settings‘ icon (the three dots) on the top right corner, choose ‘Local update‘, find the .zip file and click on ‘Install now‘ button to confirm. Wait patiently for the update to complete.
Once complete and successful, do not start using the phone normally with wiping data. Go to ‘Settings’ and select factory reset option or reboot to recovery mode and do a full wipe of the phone following the instructions below:
Turn the phone off, and then hold down both the volume up button and the power button. This will bring you to recovery mode.
Choose your preferred language with the volume keys and select with the power key
Go to ‘Wipe data’, and select ‘Wipe user data’
The phone will reboot and you will need to set up with your Google account info.