IPhone – How to create iPhone screenshots without the lock button

Plugging a phone into a computer or power source via the usb cable will power it on, even if it is off – your phone is in need of repair or replacement.

I've seen the apple logo appearing for a few seconds and then phone dying several times with dead phones. I've fixed countless phones, but I don't have a concrete answer for this problem other than it being related to the motherboard in your phone and the solution is a replacement (replacement part more than value of the phone)

I don't have any experience with jailbreak, but I think one possible solution would be to see if you can run a VNC server on the iPhone. VNC is a screen sharing protocol: the server runs on the machine whose screen you want to view and control, the client runs on the machine that you want to sit in front of.

I did a Google search for "iPhone VNC server" and came up with this link which describes how to set up Veency (jailbreak required) to do this.