Implementing an update/upgrade system for embedded Linux devices

Question

I have an application that runs on an embedded Linux device and every now and then changes are made to the software and occasionally also to the root file system or even the ins

Answer 1

You can journal an update and divide your update flash into two slots. Power failure always returns you to the currently executing slot. The last step is to modify the journal value. Non atomic and no way to make it brick. Even it if fails at the moment of writing the journal flags. There is no such thing as an atomic update. Ever. Never seen it in my life. Iphone, adroid, my network switch -- none of them are atomic. If you don't have enough room to do that kind of design, then fix the design.