I can't update my phone

[Guest ktdiallo]

trying to download firm ware updates as prompted by notification, over wi fi for my huawei g300 ascend u8815. update package verification failure every time. so resorted to using manual method following official instructions online. have managed to root phone and back up imei. then copy correct update to sd card. but when I try to update from sd card the update fails as it cannot ,,open package,,. have followed instructions on replacing file update. app but still no joy. am tearing out my hair. I just want to update to version 935 from 895. please can someone help me? I believe the update will fix the problem of quiet ring tone.