My A1 worked great for about 2 weeks before I started experiencing the restarting and the unreponsive touch screen. I'm fairly certain that My device is defective since it *always* fails the screen calibration but I cannot take steps to return it because I've already opened the back of the tablet and marked up the rear cover. In living with the tablet for about a month now I have also lost the internal speaker although headphone and bluetooth audio still works. I had a few cases where the tablet would not start and it seemed related to the back cover because as soon as I replaced the cover, it would stop working. Now I just carry it without the rear cover and this gives me access to the battery plug. So whenever I have restart or unresponsive issues, I just unplug the battery for about 2 hours to reset the device and then charge it up and start using it again. I'm probably going to replace it with a real tablet but we'll see how it goes like this for a while. thanks Chi.