Chalk up another satisfied customer of Tony's.
I got my upgraded eMMC card back today for my MCU1 MX 75D. Got the car put back together and unlike my carburetor rebuilding days, I didn't end up with a dozen leftover parts or screws. Everything tested as good except Passive Entry is permanently off whether I have the setting On or Off. The car is loading a software update right now, so we'll see if the issue clears up. All other car settings were still set up as they were when I removed the MCU.
Some observations:
1. I didn't catch this when removing the MCU, but when reinstalling today, I noticed two USB sockets on the back of the MCU, but only one USB wire behind the dash. I went back and watched Tony and David's video again, as well as another MCU removal video from Electrified Garage. Both videos were on the Model S. Both had 2 USB cables connected to the MCU. I searched for 10 minutes in the MCU opening in the dash and concluded that there is only one cable in this car. One socket was unlabeled, and the other was labeled "USB 2". I connected to the one I assume is USB 1. After powering up, I checked all USB ports in the car and they all worked. So I now believe that the USB 2 socket is possibly to allow commonality of parts with the MS, but the MX (at least my version) only uses one of the ports.
2. Believe it or not, the part that gave me the most trouble on reassembly was the rubber gasket around the frunk tub. I had removed the frunk to disconnect the battery. The trick that finally worked for me was to remove again the plastic covers around the frunk and the cloth frunk liner. I finally got the gasket on the plastic tub, then reinserted the liner and tucked it under the gasket. Finally the plastic covers went back on. I'd be interested in hearing if there is an easier solution.
3. I replaced the 12 V battery as preventative maintenance, even though I had no indications of impending failure. The car is a 2016 with 56,000+ miles. I had the battery tested and indicated marginal to weak reserve capacity. I'll keep it as an emergency spare because they aren't available at any auto parts store, but I'm glad I changed it out.
4. During the test drive I tried to load Tesla Waze on the web app. Ever since the web update pushed out in early 2019, I think, I haven't been able to get any pages to load. It did load today, but very slowly. So I'm seeing some improvement, but I think the only way I'll ever see "normal" web access again is with an upgrade to MCU2. Except for Waze, I never used the web, so this isn't a huge loss.
5. One pleasant surprise. This was the first time I've removed the frunk and discovered I have the large HEPA filter behind the frunk tub, even though this car does not have PUP or Bioweapon Defense mode. It was built at a time that Tesla was struggling with MX production so it's likely they were cranking out a number of similar configurations and just changed the software.
I'll echo what others have said about Tony's customer service. I was extremely pleased. All email questions were answered promptly, he kept me informed of the upgrade progress, and the turn-around was only 3 days plus shipping time to-from Colorado.