I tried with a usb stick. Couldn't get to bash prompt, think it might be hanging looking for root on an sd card. Since the instructions say use an sd card, assuming it's my fault. Chrooting seems to work just fine..except the networking seems messed up. Can hit ip addresses, but not domain names. But here again, I'd guess it's some dumb mistake that a little rtfm and troubleshooting should fix.