Nice sentiment, but hard to deliver. You have a dishwasher and a fridge, right? They've been running firmware you don't get to inspect for a couple of decades already. Luckily they don't have network access.
How many years is 'decades'? About 4 or 5 years ago I took apart a freezer that was about 10 years old. The compressor seemed to be switched by a thermostat; I found nothing that would have firmware.
