Get in touch with the assistance team via att customer service. Also, along with that, you have to hold your Galaxy S8 and Galaxy S8 Plus by clicking on the button for a volume. By using a USB cable, connect the computer to the smartphone while keeping the Volume button. 1-833-554-5444
United States, Computer, Turn on Galaxy S8 without using the power button get Att Customer Service 1-833-554-5444