01/18/2012, 11:22 AM
I've experienced this while trying to recover from the last WebOS update. In my case, it turned out to be a defective connector on the micro USB cable. Cable had been working fine, but I noticed that the "Battery charging" notification never appeared, and the battery level keep dropping while plugged into the AC adapter. (And yes, I checked to ensure the adapter wasn't unscrewed.)
Shortly after that, got the no devices connected message while attempting to install Preware. Got the same message from two computers, so that just left the cable and the Touchpad as suspects.
Picked up a USB - micro USB adapter (type B, I **think**) and it's now working fine. Tried the old cable with the charger again to confirm that it was bad, and wound up glitching the Touchpad and locking it up. Took a hard boot (power + home for 30 seconds) to shut it down. Seems to be back to normal after reboot.
What's the warranty on the cable? Can I get it replaced by HP?