Application image unable to control some GPIOs when mcuboot enabled

RE: Application image unable to control some GPIOs when mcuboot enabled

Simonr — Fri, 21 Nov 2025 07:55:30 GMT

Glad to hear that. Closing this ticket then. Don't hesitate to reopen it if there are any follow-ups, or create a new ticket if the subject isn't directly related to this.

Best regards,

Simon

RE: Application image unable to control some GPIOs when mcuboot enabled

Redrield — Thu, 20 Nov 2025 21:30:13 GMT

Thank you! The documentation about adding overlays to mcuboot was exactly what I needed. While I agree that a custom board definition would be preferable, I wasn't able to get it working properly when I tried to make a custom board in the initial revision of our custom hardware.

RE: Application image unable to control some GPIOs when mcuboot enabled

Simonr — Thu, 20 Nov 2025 13:40:57 GMT

I think what you're seeing is that MCUBoot is printing out the pinouts it has gotten from the build here. The app.overlay file will only overwrite the UART pins for the application, while any sub images (like MCUBoot for example) would still have the default board settings.

The recommended way to go about this I think would be to create a custom board file rather than using an overlay for the DK board file. If not you will need to make .overlay files for each of your sub images in your project. We have a lesson on DevAcademy explaining how you shouuld go about creating a board file suiting your custom board available here:

https://academy.nordicsemi.com/courses/nrf-connect-sdk-intermediate/lessons/lesson-3-adding-custom-board-support/

Alternatively, the Bootloaders and DFU/FOTA lesson explains how you can create an .overlay file specifically for MCUBoot as well. https://academy.nordicsemi.com/courses/nrf-connect-sdk-intermediate/lessons/lesson-9-bootloaders-and-dfu-fota/topic/exercise-1-dfu-over-uart/

Best regards,

Simon