My M835 originally had the Build 622 software installed (B622 at the end of the version number). It has since been upgraded to Build 666 (B666) that was provided via Huawei's web site. If I do another factory reset of the phone, will the phone revert back to B622, or will it reinstall B666? The upgrade directory and files for B666 remain on the SD card, I did not remove them after it was upgraded. Thank you.