https://devzone.nordicsemi.com/f/nordic-q-a/120065/mcuboot-no-external-32khz-crystal-sysbuild-issueI have been trying to: add MCUBOOT and FOTA to a custom BLE board using the nRF54L15. I had thought that the sole issue was that the custom board does not utilize and external 32KHz crystal. This easily managed in the main app by adding the followingen-USTelligent Community 13Sun, 23 Mar 2025 22:14:15 GMThttps://devzone.nordicsemi.com/thread/528513?ContentTypeID=1Sun, 23 Mar 2025 22:14:15 GMT137ad170-7792-4731-bb38-c0d22fbe4515:898b8401-04d2-4ce7-be5a-62496599f419Evluma<p>I have found the issue finally. It was a file naming issue. although I am using the *_ns version of the build the files in:</p> <p><span>{$project_dir}/sysbuild/mcuboot/boards/</span></p> <p><span>had the _ns added to the end. The sysbuild system did not see them as belonging to the project even though the project is _ns. simply removing the _ns from the end of the files allowed the files to be read properly. I am not sure if this is by design or an oversight as this is true for the .conf file and the overlay file and those are certainly important distinctions in the main app.</span></p> <p><span>Thank you</span></p> <p><span>Warren</span></p><div style="clear:both;"></div>