no, it just has to be signed, if you can match the file size, sometimes it works.
ota's are signed. depending on the level of security, it could have to match the checksum, but most likely size is all that matters
the point with the OTA being usable to us, is that it rewrote recovery(if that truely is the case) recovery is supposedly locked, so this can possibly help with writing a recovery.
and potentially show us the security they are using to prevent writing to partitions
adrynalyne?? you have the incredible now? I thought you were on the moto droid. Man if there was ever hope that we'd get a rooted incredible, I'm sure you'll find a way. I can't get over how many i910 users have made the switch to android. I guess for now we are in a waiting pattern till we get a leak...
also do you have any fear that the sense overlay will delay the incredible from getting 2.2 in a reasonable amount of time? most HTC android phones are still at 1.6 I'd hate do be stuck to 2.1 because of the sense integration.
I have an Inc., but I do the whole rom/modding thing on the Moto Droid. I just needed a phone to be my daily driver while I work on stuff. I had the same problem with my Omnia, where I was flashing so much I couldnt use the phone as a phone lol.