1-read rom2 , rom3 , and extcsd if you have not formated it
2-check emmc smart report if it is abnormal or read only than make gp partition
3-full erase
4-write rom2 ,rom3 and extcsd
5-select write by vender select MTK and write scatter firmware
some mtk devices boots with only write scatter firmware a video link is here
https://www.youtube.com/watch?v=4sobo6u2YcM