camera shows horizontal line moving from down to up
 

the lines are moving in a constant frequency the effect is very similar to when you try to shoot a video of a CRT tv.

could it be hardware damaged/, because I drop it way too many times

I did 3 flashes without flashing the emmc, still nothing changed.

Re: camera shows horizontal line moving from down to up
 

Maybe? Do the troubles appear in the recordings?

Re: camera shows horizontal line moving from down to up
 

Sounds like a hardware fault then, you could try using a alternative OS to see if the camera works correctly there but I'd guess not.