smp_srv FOTA on nrf5340

[SoukTi]

Hi,

We are running the smp_srv on the nrf5340 NET Core, we suspect the example is writing the firmware image to the NET core instead of the APP core.
How do we have to modify the server for it to write to the APP core instead of the NET core, We are running a MCUBoot bootloader on the APP core that enables
the NET core at bootup.

[Simonr]

Hi

The firmware is not written to the NET core. In fact, it's not possible for firmware running on the APP core to access Flash of the NET core.

To enable NET core updates on the nRF5340, you need to choose this in kconfig, and then use smp_svr to load the NET core update into the MCUBoot secondary slot in the APP core flash. On the next reset, the update of the NET core will be done.

To choose whether it is the NET or APP core that gets updated, it's a matter of picking the correct file (app_update.bin or net_core_update.bin I think)

Relevant documentation:

• https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/ug_nrf5340.html#fota-upgrades
• https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/samples/nrf5340/netboot/README.html#nc-bootloader
• https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/include/dfu/pcd.html#subsys-pcd

Best regards,

Simon