I work on that software too (again not Tesla). One other thing - often the hardware we get is per-production and has a list of errata that will be fixed before production. They don't want to make too many of these for engineers because it is done in a fast turn-around higher cost factory and it is expected that once in a while things won't work at all (someone forgets to connect power to the CPU pin or something similarly stupid that requires a lot of manual wiring to fix on each one). As such you have to justify getting any controller and often share. Once the product is shipping they make many of them and it isn't a big deal to get one on your desk - but you have now moved onto the next thing and so the problem returns.