I had an otherwise successful MCU replacement a week ago. I gave my list to the Ranger to be sure everything was working before he left. They don't give these guys enough time to actually complete the reprogramming, so he left while the car was still updating itself.
I told him about my concerns that the app wouldn't unlock the car, and they needed to reset the MCU Command Key. He said he had never heard about that, but if it was a problem to text him.
And of course, the app won't unlock the car from the app.
I texted the Ranger, and he replied that they would send a newer build of the software to me. They did, it updated, and the car still won't unlock from the app. I texted that they needed to reset the MCU Command Key.
They replied by text that they would have somebody do it. Nothing changed.
Five days later I call Tesla support, do all the preliminary dance for 10 minutes so that they can actually read your records, and the tech support has never heard of resetting the MCU Command Key. They suggested that I reboot the car a few times and reinstall the app.
When I told him that I had already done those things, he entered a ticket for the Ranger to come back in a week. I told him that seemed unnecessary since I had seen (here in this thread) that it could be done remotely. He said he would put in a ticket to do that, but scheduled the Ranger anyway.
It sounds like Tesla still needs to refine the MCU replacement process. I still can't control anything from the app. And they are wasting Ranger time on stuff they can do from home base.