> You can use a write-once hardware register at the end of the boot sequence for similar effect. Or use a turn-key switch. First put it into II, wait for the b

> You can use a write-once hardware register at the end of the boot sequence for similar effect. Or use a turn-key switch. First put it into II, wait for the boot sequence to complete, switch back to I. Yes, that does require someone to be on site but that tends to happen anyway when someone restarts the ATM in the first place. If you want to update the software remotely, you could download it into ramdisk and run it from there. For the base system, you'll want something robust so it's more or less guaranteed to get to the point where you can manage it remotely. And you could verify the downloaded application bits against a locally installed root certificate. The old MS-Windows-based ATMs may be rebooted daily, but let's face it, that's just because Windows. When the base system has to be updated for some reason, a service technician will have to physically replace the storage device for it. If that happens very often, they're either doing it wrong or I'd recommend against such a setup. But perhaps the vendor can charge for the service, in which case /care ;) Or they could turn the key into II every last Monday of the month for example (the ATM would go into maintenance mode) at a certain time and let the big maintenance server do its work overnight, avoiding the situation altogether at the cost of a slightly greater risk that the machine becomes defective. In any case, a tiny embedded OS would be perfect for the job.