I have a 2017 Model S 90D that has developed a serious LTE connectivity problem (roughly 50% no-service) over the last month or so. It’s tough to timeline it to any particular event, but I would say that two things happened around the same time that I started noticing this: 1) I upgraded to the .12 firmware (and it is still stuck on .12....) 2) I had my large middle screen replaced for a yellow discoloration around the perimeter of the screen. The symptom is no very frequent no cellular coverage - no bars with a line thru the icon. Often an MCU reboot from the screen will bring it back to live temporarily. This has gone from a minor hassle to a major usability issue with the car - no maps, no traffic, no voice control, .... Has anyone else had an issue like this? I should note that home base is upstate NY (about an hour north of the city) with perfectly adequate AT&T coverage on phones. Today I drove from manhattan to boston and back with the issue happening for up to an hour at a time.