Chosen Solution
I have an iPhone 6s Plus that was given to me, to fix, and I have no idea of what has happened to it in the past. When opening the phone, I accidentally touched something that caused a small spark. I do not know if this has contributed to the problem. When powering on the device, all that shows is a quick flash of an apple logo, and the a connect to iTunes screen. Once in iTunes, I am directed to restore the phone, that it cannot be updated. The phone will start to restore the OS, and then I get an error 9.
Error 9 is a early disconnection at restore. Depending on where the spark came from I would say that you could have shorted the tristar or nand rails. You will most likely need to have the board repaired by a micro soldered
