I think Porsche (and related brands) also have this or a somewhat similar vulnerability. Owners use it to add Android Auto to a car that formerly only supported Apple Carplay.
Eventually a better vulnerability was discovered where the signature validator didn't work properly:
The vulnerability used there is explained here: https://github.com/jilleb/mib2-toolbox/issues/122 . It's a "classic" mistake in signature validation (iirc the Windows software licensing service had a similar vuln at some point) but is a lot less trivial than this one; basically, the signature validator would stop validating once validation succeeded, so it was possible to take a valid update manifest and just tack more instructions onto the end of it and it would happily run them (the validation would return True, and then the command-runner would happily iterate through everything it got).
There's also a vulnerability on the lower tier models that revolves around a logic error and a signed update which would copy unsigned files into a directory due to some issue with the path validation that I can't completely recall at this point, as used in https://github.com/olli991/mib-std2-pq-zr-toolbox .
Anyway, these were a lot more exciting from a vuln research standpoint than this one (the MIB head units are also _fascinating_; they are not standard Tegra Android devices but a morass of rare and exotic DSP hardware driven by QNX and a giant enterprise IBM Java applicatoin).