When you need to flash your device am described above complaints always use latest firmware version for successful flash. Vivo AFT flash tool asks credential login to run the flash tool and authenticate from Vivo server to verify you are a authorized user then only the tool open for flash. Without username and password you cant run the tool and cant flash. If you don’t have the login access contact me for flash service by Remote connection like Team viewer its not a free service always paid service and price fixed.
I am Completed my post graduate at 2014 there after am start my carrier as Smart phone repairing Hardware and Software , So much am interested to do writing articles and content about technology so that am here for you and yours learn more about smart phone repairing and tech news.