Akikiki
A'-Lo-HA ! y'all
I don't know either. Want to guess? Want to speculate? That's all it is. We don't know what we don't know. We do know there's a shortage of LCD screens. We know there's been a shortage of chips, and its adversely impacting availability of new or refurbished daughterboards. So, if there's S/X with a marginal eMMC, maybe - just maybe they don't want to push a minor update to it, because a fresh update could cause a car to not boot again after an install.I have gotten multiple updates on my MCU1 HW3 car since the start of 2021 — IRC, 2021.48.37.2, 2021.48.37.3, 2021.48.37.4, and 2021.48.37.6. These cars aren't failing to get updates. They're getting updated. The updates are just branched from a really, really old baseline version. And this is affecting every single car with MCU1 and HW3, but doesn't appear to affect any cars with MCU1 and HW1 (non-upgradable to HW3), which are all much older than anything with MCU1 and HW3.
So this has nothing whatsoever to do with eMMC wear. There is a small possibility that it is caused by eMMC *size*, of course.
I don't know why they aren't pushing current firmware revisions to MCU1, but my guess is that they haven't figured out a way to optimize the code enough that the city driving code doesn't bring MCU1 to its knees. My strong suspicion is that they will end up replacing MCU1 with MCU2 for FSD users before this is all over. It's probably way cheaper to do that than to spend resources trying to support city driving on MCU1. Expect the price of FSD to jump way up when they make that decision, though, and expect them to drag their heels as long as they can get away with it, because everyone who pays for the MCU2 upgrade right now is one more upgrade that Tesla won't have to pay for later.
The eMMC contains to complete versions of the firmware. The current which the car boots and runs with, and the last/more recent before the current. We (being owners) can not simply trigger and older one on our own. Each time another OTA update is received, it downloads for installation to the older partition on the eMMC which contains firmware. Its some what like "A" is current and "B" is older. When a new download occurs, it next goes to "B", and "B" becomes current. If one of these partitions is marginal or worse - bad, the update may not download, it may download partly and fail to complete. If it can't complete a download, it will not even attempt an install.
With the logistics issues of getting eMMC daughterboards and refurbished MCU1s, - you are right, maybe they are not pushing fresh firmware.
These download/install issues have been discussed in several threads. What I am describing is not news. Its just not been discussed in a while, since we've moved past "is it an eMMC problem or not" - finally.
BTW, I am not saying anything you said in not correct. I am just saying we don't know with certainty, what is going on, or why some cars are getting more attention than others.
I do know that for more than a year, when I was on MCU1, it was a year before I could get a fresh update. I know I had a failing MCU1 from more than one problem. And now that I am on MCU2, I get an update every 2-3 weeks.