So what, automotive developers never make silly bugs?
Case in point: Audi Concert/Chorus radios used in early 2000s. Turning volume knob worked like that: after every knob turn save updated value to EEPROM, then immediately read EEPROM and send that value to audio chip.
Inevitably, after many years EEPROM cells storing volume died, causing that turning volume knob just set volume to totally random value. It was impossible to repair, as EEPROM wasn't separate chip but was integrated in MCU. And you couldn't easily replace MCU because it contained mask ROM code. The hack that was sometimes done was: add custom microcontroller, connect it to the knob, splice I²C wires to audio chip, and patching volume set command on the fly...
Case in point: Audi Concert/Chorus radios used in early 2000s. Turning volume knob worked like that: after every knob turn save updated value to EEPROM, then immediately read EEPROM and send that value to audio chip.
Inevitably, after many years EEPROM cells storing volume died, causing that turning volume knob just set volume to totally random value. It was impossible to repair, as EEPROM wasn't separate chip but was integrated in MCU. And you couldn't easily replace MCU because it contained mask ROM code. The hack that was sometimes done was: add custom microcontroller, connect it to the knob, splice I²C wires to audio chip, and patching volume set command on the fly...