extending nRF91 support

[maxd-nordic]

Hi!
I've been looking at nRF91 support in BMP. It's nice that we have basic support already, but two things are missing:

• APPROTECT recovery
• modem firmware update

I could try to help implementing this. This recovery mechanism seems to relatively straightforward to integrate into BMP, but what about the modem firmware? We deliver it as a zip file and there is a long-ish sequence to get the job done (see here). How would you approach this?

[dragonmux]

👋🏼 Agreed about the "APPROTECT" mechanism being fairly straight forward. With the modem firmware upgrade, BMD being firmware accessed over USB (ignoring, for a moment, BMDA which is another story) we would suggest that the "setup device" logic can be integrated into the nRF91 support directly, but that the actual loading of the firwmare would need to be done either via a tool like bmputil/bmpflash or by wrapping the blob up for GDB and using GDB's load mechanism.

This is particularly of note as we have neither the Flash space, nor the capacity as a USB device to go ingesting a Zip file w/ just 20kiB of SRAM to work in, so any preparation needed of that component must be done by the user or at least on the user's machine.