No command signal on my screen, why?

A

AC Question

no command signal on my screen, why?

i have gone through a system update in my mobile and while installing it..i got an error message. after that my phone isnt responding. its showing me no command signal.tried factory reset through hard buttons but still after that while rebooting my mobile, its just showing me the logoscreen. my mobile is htc desire 816g. pls help me.. :(