Merkman, "C" should replace everything 3100 put on. If you have trouble hard reset and try again on a clean device. I disagree with the need for 3100 first. But they were correct on the shutting off the radio to get around memory error. 3500 replaces everything. The confusion was the unpredicability of memory errors which I think I narrowed down. Behavior however may be different on VZ6600.