If you're wondering whether removoing the back cover on the NC will void your warranty, yes it will. I spoke to customer service on 092511 because my SD card would come out and I removed the cover to recover it. I was told I was not authorized to remove the cover and therefore I voided the warranty. I can't use my SD card slot now. I was gonna go to a B&N and make sure this is true. I wouldn't have had to remove the cover if it wasn't for the fact that the SD card got stuck in the slot. You can see the full text here:
http://bookclubs.barnesandnoble.com/...1166126#M60852