Mcuboot location in-tree/out-of-tree with sysbuild

[m5k8]

I'm migrating my app from parent/child to sysbuild.

Previously I had both bootloader and firmware as separate out-of-tree projects and that was working fine.

Now using sysbuild, my firmware is still located out-of-tree, but mcuboot gets compiled from ncs tree.

That doesn't suit me, because I have modifications to mcuboot source code, I need to control some GPIO before mcuboot does it's lengthy work.

Modifying mcuboot that's located in ncs tree is possible, but not reasonable.

How to achieve my required mcuboot modifications in such circumstances?

[Vidar Berg]

Hello,

You can maintain your own fork of the SDKs bootloader project if you want to modify the code, see https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/dev_model_and_contributions/adding_code.html#workflow_4_workspace_application_repository_recommended . Alternatively, if you only need to control the GPIOs before the bootloader runs, you can define your own board with some custom initialization code for the GPIOs.

Best regards,

Vidar

[m5k8]

Vidar Berg said:

you can define your own board with some custom initialization code for the GPIOs.

Maintaining my own fork for few lines of additional init code seems problematic.

Your suggestion looks interesting, but how to add custom initialization code at board definition level? I didn't find any recipe?

[Vidar Berg]

m5k8 said:

Maintaining my own fork for few lines of additional init code seems problematic.

I probably wouldn't have considered this either if it was just a few lines of code. Maybe just add the changes manually or through a patch file. 

m5k8 said:

Your suggestion looks interesting, but how to add custom initialization code at board definition level? I didn't find any recipe?

Have you defined your own custom board yet? In that case, you can specify additional source files to be included in the build when your board is selected. For example, like how the thingy53 board include the board.c file here: https://github.com/nrfconnect/sdk-zephyr/blob/763e6a8ab82bd1a346a9b14a4b8fc7509c8441b6/boards/nordic/thingy53/CMakeLists.txt#L6 that will run this setup() function: https://github.com/nrfconnect/sdk-zephyr/blob/763e6a8ab82bd1a346a9b14a4b8fc7509c8441b6/boards/nordic/thingy53/board.c#L47