I'm thinking about upgrading my older Tivo unit via the Instant Cake and PTVnet software.  But..., as it stands right now my older Tivo unit is incapable of showing my local channels.  The (not much newer) DirecTV unit had no problem with the 2 dish into one cable to the back of the receiver setup.  It was able to "see" the DirecTV channels from the one dish and the locals from the other.  My present Tivo unit for some reason can not do that.  My local electronics retailer says it's because it's an older unit and was incapable of doing this.  He said the newer units wouldn't have a problem.  If I perform the Instant Cake and PTVnet upgrade to my older unit - can that then enable it to "see" the local channels?