Very VERY interesting. Mine boot looped once, my husbands got stuck in a boot loop no matter what he did so they replaced it at the store (now he wants a Razr coz he thinks we shouldn't have this bad of a glitch, I dunno). Didn't try booting without the back though.... But since we all know the back houses part of the antenna-- and I saw in another thread that its some kind of glitch where the phone is trying to authenticate to the network when it's booting (and when it fails, it boots again thus causing the loops)... Might be something wrong with the antenna/housing? This is one where I can't really tell if its more software or hardware related... Probably software though... It could even be a glitch with the software/device trying to communicate through that part of the antenna on the cover and fails... In the other thread the guy said they've reported (vzw) it to htc and its some batch of phones that got corrupt versions of software. I don't know how true that is being that I read it from another's post but thought I'd share what I found.