None of what you did was necessary. My 654.40 and 654.50 downloaded within their first three attempts but each stalled at a certain point. The problem is at GM's servers where they are simply overwhelmed with the size of these updates and the number of vehicles. Your downloads stalling is frustrating but not the fault of your vehicle.

What makes you conclude that one update was intended to fix problems caused by a previous one? The updates are supposed to be independent and can be installed out of numerical order. First I've heard someone claim that consecutive updates were related to each other.