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My prior post is the way to fix this problem of the eMMC chip 'wearing out' with age. In early years Tesla did extensive logging which writes to /var in this chip. This Hynix chip is not very good quality, and anyway chips not labeled 'endurance' or similar can't take too much writing.
The result is at some point, now affecting cars 2016 and older, the eMMC will wear out, the Tegra processor will not be able to boot, and your MCU screen will be black or the MCU will reboot and reboot. This is inevitable, unless one of these commercial rooters has disabled logging. Most ppl have their MCU replaced and reprogrammed, but all that needs done is the eMMC chip replaced. I believe I'm the first to suss this out three years ago.
Myself, I replaced the 8GB Hynix with an industrial-grade SwissBit chip as I'd detailed before.
So doing the rework to remove and replace this chip is risky. And once the MCU is dead it is not very likely you'll be able to recover the /var partition, which is partition 3 on the chip. It would be a very good idea to get a dump of the chip before it fails so here is a less risky way to do that.
MMC/SD is actually an interface standard which allows different manufacturers to make chips that are drop-in replacements. If you don't want to replace the chip for now and just dump it, you can solder fine wires onto the right pads on the back of the CID, connect those to the AllSocket's header pins, and read the eMMC that way.
This isn't one of those easy things to do. It's not for shoe salesmen... worthwhile things are rarely easy. But if you've a steady hand and an accurate mind, you'll be fine.
 
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