Just setting the clock on your Apple device to January 1, 1970 will permanently brick it. And it overheats as it dies…
By setting up your own time server and Wi-Fi hotspot it can be done remotely to most Apple devices that come within range.
Update your Apple device software. Or, considering using it to fry an egg on as it’s last functional activity.
My first thought was that it was something to do with the UNIX epoch time, but it turns out to be more interesting than that.
Apple actually went and implemented the HCF instruction.
It takes a very high level of incompetence to build a system where the thermal management works only if the clock is set correctly.