Adding demo bootloader for nrf54L15

[reichel]

I do step-by-step elements from https://academy.nordicsemi.com/courses/nrf-connect-sdk-intermediate/lessons/lesson-9-bootloaders-and-dfu-fota/topic/exercise-5-fota-over-bluetooth-low-energy/

Using LBS sample, NCS 3.1.0, toolchain 3.1.0 and finally  No configure step for 'mcuboot', as mention in sysbuild.conf have only this

SB_CONFIG_BOOTLOADER_MCUBOOT=y

in prj.conf

CONFIG_NCS_SAMPLES_DEFAULTS=y

CONFIG_BT=y

CONFIG_BT_PERIPHERAL=y

CONFIG_BT_DEVICE_NAME="Nordic_LBS"

# Enable the LBS service

CONFIG_BT_LBS=y

CONFIG_BT_LBS_POLL_BUTTON=y

CONFIG_DK_LIBRARY=y

CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048

CONFIG_NCS_SAMPLE_MCUMGR_BT_OTA_DFU=y

Not sure what goes wrong (and feel that documentation changes too fast ... too many versions in a short time)

[reichel]

With config nrf54l15dk/nrf54l15/cpuapp build with success

Memory region         Used Size  Region Size  %age Used
           FLASH:       41224 B        54 KB     74.55%
             RAM:       22200 B       188 KB     11.53%
        IDT_LIST:          0 GB        32 KB      0.00%

so, what to do with configuration nrf54l15dk/nrf54l05/cpuap ? What settings should be applied to fit in a memory (error: section `datas' will not fit in reg ion `FLASH').

[Amanda Hsieh]

Hi, 

reichel said:

what to do with configuration nrf54l15dk/nrf54l05/cpuap ?

nRF54l05 has limited internal flash. Please choose another chip with a larger internal flash or use it with an external flash. 

Regards,
Amanda H.

[reichel]

This is really sad. Because even on L10 could not fit if a simple "hello world" takes 74% from L15. This rise cost of the device (especially if this is a simple device). Now, when code development can be quite dynamic (therefore, there is a chance of a bug in the application itself, Zephyr, and also BT stack). Additionally, EU regulations and CRA requirements mean that most clients require the FOTA option (and there will be a chance that it could be obligatory for such devices).

[Amanda Hsieh]

I would suggest you use an external flash for DFU. See this course https://academy.nordicsemi.com/courses/nrf-connect-sdk-intermediate/lessons/lesson-9-bootloaders-and-dfu-fota/topic/exercise-3-dfu-with-external-flash/ 

[reichel]

What benefit (additional component, more space on PCB, emc, ...)? This will also cost and not sure that we can achieve a really lower price, for example for 10k pcs for external 1M flash which will be much more lower then the difference between the price of L05 and L15 ? Must check.