I beilieve you can just plug the internet into your 3808 and do the firmware update through the on receiver display menu, so there is no need to hook it up to a tv.
tv might make it easier though.
But to answer your question, the firmware does not require anything to be setup prior to the install. In fact, it is probably best to do the firmware update first. when upgrading fromt he 1st firmware that came with the 3808 all of your settings got reset anyway. (I think that the models being sold now have this problem resolved so it should'nt be an issue though).
