i tried to update phone OTA and it didnt reboot after that. it was on boot loop. it came up with message system failed to start would you like to perform factory reset?. i didnt want to lose my data so i rebooted and tried to flash everything besides user data via sp fash tools. it said successful but now it is just black screen, no blackview logo. if i try to reflash it with spflashtool it just gets stuck at download DA 100%. how can i fix this?