I would use fastboot commands to erase userdata, erase cache, flash a new userdata.img file, boot into recovery, wipe data, wipe cache, reboot.
fastboot erase cache
fastboot erase userdata
fastboot flash userdata.img (the img file needs to be extracted from the stock ROM currently installed on the phone)
After flashing usedata.img file, do not reboot yet. Select recovery using volume button from fastboot menu, wipe data, wipe cache, reboot.
Of course, do this will completely wipe data from the phone.
If the above doesn't work, reflash the entire stock ROM (recovery, cache, etc.) and perform the above steps before booting the phone for the first time.
Last edited by audit13; 20th January 2016 at 02:38 AM.