I'm reading up on signed updates. Based on my understanding I could embed the public key on all my devices and then any new firmware needs to have a signed hash that I could check against. This is great for secure updates, but I'm wondering how one would securely store the private key. Say I built 1M units. All have this public key programmed. If this private key is lost, I basically lose the ability to update any of these devices. So while it's great for security, it also sounds like the jugular vein. Am I missing something?