Acer Iconia One 8 Service Manual page 18

PS. Don't disturb or plug out the USB cable for instant, to avoid image broken within image download
period.
4. When image download finish (as below 100% progress drawing), please push "power" key to make the tablet reboot.
PUSH
Download finish
5. Connect the AC ADP, and Reset to default
Reminding: It's better no plug out the AC Adaptor until reboot process finish!
6. After device auto reboot and restart the device, can finish the image download procedure.