what are possible ways to safely update firmware on nrf51822 from other host processor ?

[jitu]

I have having following configuration:

I want a fail safe method to update firmware on nrf51822 using attached host controller. I looked at serial wire debug interface and serial boot loader. Is there any other means to do it. Any reference available for doing it any similar example?

[Vidar Berg]

The serial bootlaoder from the SDK should be well suited for this. There's also a blog post on it here.

It should be possible to use the debug interface as well, but that would require the SWD ARM coresight DAP lite protocol to be implemented on the host controller.