I’m pretty sure it’s safe to say there are more HP TouchPads left in the world than there are their matching original barrel chargers. This means if you have a TouchPad today, you’re probably using a TouchStone, a computer, or any other random USB A charging brick to (very slowly) charge your 13 year old device. And it means you’ve seen the error message in the image above every time you’ve plugged it into anything other than the original barrel charger or a computer. Fun fact, you can trick the TouchPad into charging normally and not feeding you the message by creating your own custom micro USB or USB C cable if you’ve modified your TouchPad.