Add source code to mcuboot with sysbuild

[Anthony Ambuehl]

NCS 2.6.0, sysbuild with mcuboot

nrf52840

I'm trying to add  LED indication during mcuboot image transfer.  Currently it takes 20-30 seconds for the image copy and the end-user is concerned the DFU has failed.   

I have modified my mcuboot setup to include the necessary drivers, but I need to add some code to do the following:

* during system startup set an initial state for the LEDS

* as progress is made in the image copy, alter the LED to indicate progress.

Ideally I want a way I can add a SYS_INIT in source code outside of mcuboot repository itself so I can avoid forking mcuboot code.  I was initially thinking to add code in the app/src folder or in app/sysbuild/mcuboot/src...

[Anthony Ambuehl]

I added a custom library that I only enable through mcuboot.conf.

I found the existing CONFIG_MCUBOOT_ACTION_HOOKS variable to get some notification for starting the upgrade process.

Unfortunately I don't see any hooks in the code to indicate progress during the move/copy.

[Amanda Hsieh]

Hi, 

As far as I know, Sysbuild does not let you override any source code.

The hooks only support the status as the list here. 

Regards,
Amanda H.