NRF54L15 - issue when MCUBoot/Partition Manager is used on a custom board

[Alex P]

Dear Team,

I am experiencing a weird issue with the firmware on my custom EV board with NRF54L15.

My firmware is using MCUBoot and partition manager (I use a separate flash partition for storage) and it runs just fine on my NRF54L15 DK board.

However, once I program it to the custom board, it just doesn't start.

I have also noticed in NRF Programmer that there is always a difference in memory layouts between File and Application (unfortunately, to some reason it is not allowing me to read the memory from DK board chip). Specifically, after flashing, the application size becomes around 3 kb smaller,9 kb storage partition (in the middle) shrinks to 32 bytes while MBR (orange partition) becomes bigger by approximately the size of the storage partition.

Once I remove MCUBoot and Partition Manager dependencies from my prj.conf, I am able to run the firmware (but obviously, it now won't be able to use storage and MCU Boot).

The firmware gets built for NRF54L15DK board and nrf54l15/cpuapp qualifier. 

What could be the issue?

Thanks

[Alex P]

Dear Team,

It seems that as my custom board is using internal RC for LFXO (it doesn't have 32 KHz crystal installed), it seems that issue might be somehow related to MCUBoot not using proper crystal selection settings. Can someone provide a guide on how to configure MCUBOOT to select internal RC for LFXO?

Thanks

[Vidar Berg]

Thanks for the update. Yes, MCUboot will be built using the default configuration for your build target, which for the NRF54L15 DK is the LFXO. If you want to change this, you can create a folder named sysbuild in your project directory, and then add a new file in that folder named mcuboot.conf with the following line:

CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y

Then perform a clean build to allow the build system to detect that a new configuration file has been added ( a clean build is only needed when adding new files, not when editing existing configuration files).

For more details on how this works I recommend having a look at this course: https://academy.nordicsemi.com/courses/nrf-connect-sdk-intermediate/lessons/lesson-8-sysbuild/ 

Best regards,

Vidar