i want to thanks hovatek for there well organised firmware i have a tecno s1as pro this was it built no.[ h8016n-gokesf-180613v69] i tried find it online but with no success then i decided to risk and iused factory signed firmware from hovatek[ h8016n-gokesf-181121v119] and its work perfect so anyone with such problem dont worry use factory signed from hovatek is very ok