nRF5 DFU over-the-air bootloader prevents wired flashing

[Jarmo]

When we use nRF5 bootloader provided with SDK the first application flashing must always be done using DFU over-the-air. Only after that it is possible to re-flash application with a wire, using e.g. segger j-link. This applies both, nRF51 and nRF52, and at least SDK8 and SDK12.

This is a problem since when we flash our customer's devices, it is too slow to use DFU over-the-air. We want to do first flashing quickly with the wire.

I guess the bootloader checks existence of an application, and if it's not flashed using DFU over-the-air, it does not start application at all. Even if it is there, but flashed with a wire. How to go around this check, and where it is placed in the bootloader code?

[Wojtek]

This should help. You have to validate bootloader settings.

[Jarmo]

Yeah, but I am developing the bootloader and the application at the same time, and I need to flash both of them frequently from the uVision IDE, or using nRFgo Studio. So the thing to add needed bootloader settings should be automated into the bootloader build procedure, or into the application build. I guess it might be possible with uVision User steps, well? If not, Makefile would also help, so what (commands) needs to be added into the bootloader Makefile to get a single hex output including the mentioned settings?