Custom Net Core DFU Files for NRF5340

[dev_j]

Hello, I need help understanding how MCUBOOT produces signed_by_b0_app.hex file from app.hex on the network core of nrf5340. My goal is to have a DFU updatable hex file (net_core_app_moved_test_update.hex), and from what I understand I can get it by signing signed_by_b0_app.hex with imgtool. I am using ncs2.6.1 and using IPC sample that has a remote as a child image running on the network core. I am able to produce the app.hex, zephyr.hex, remote_merged.hex, andd zephyr.bin for the network core, but I can't get the net_core_app_moved_test_update.hex, net_core_app_to_sign.bin, or net_core_app_update.bin. Please help. I also tried to migrate on ncs2.7.0, but when I enable SB_CONFIG_SECURE_BOOT_NETCORE, I get partition errors. Anyone with a guide on how to build a DFU updatable custom network application for nrf5340, with sysbuild or child image would be appreciated. I am currently trying to get \nrf\samples\ipc\ipc_service working. Thank you.

[AHaug]

Hi,

There are a two separate topics here as far as I see. Typically I would recommend you to create separate cases for separate topics, but I'll handle both topics in this case for now.

Hello, I need help understanding how MCUBOOT produces signed_by_b0_app.hex file from app.hex on the network core of nrf5340. My goal is to have a DFU updatable hex file (net_core_app_moved_test_update.hex), and from what I understand I can get it by signing signed_by_b0_app.hex with imgtool. I am using ncs2.6.1 and using IPC sample that has a remote as a child image running on the network core. I am able to produce the app.hex, zephyr.hex, remote_merged.hex, andd zephyr.bin for the network core, but I can't get the net_core_app_moved_test_update.hex, net_core_app_to_sign.bin, or net_core_app_update.bin. Please help.

The first is your custom net core DFU files. Lets stick to 2.6.0 without migration for now, since the change to sysbuild requires some work. What do you mean with Custom Net Core DFU Files for NRF5340 or rather " My goal is to have a DFU updatable hex file". Are you referring to new firmware for the netcore that will replace the existing, currently running firmware you have present?

Depending on the answer, the solution you might be looking for could be present here: https://academy.nordicsemi.com/courses/nrf-connect-sdk-intermediate/lessons/lesson-9-bootloaders-and-dfu-fota/ with focus on 

• https://academy.nordicsemi.com/courses/nrf-connect-sdk-intermediate/lessons/lesson-9-bootloaders-and-dfu-fota/topic/dfu-for-the-nrf5340/ 
• https://academy.nordicsemi.com/courses/nrf-connect-sdk-intermediate/lessons/lesson-9-bootloaders-and-dfu-fota/topic/exercise-5-fota-over-bluetooth-low-energy/ 
• and/or any of the hands on exercises relevant for your DFU solution

I also tried to migrate on ncs2.7.0, but when I enable SB_CONFIG_SECURE_BOOT_NETCORE, I get partition errors. Anyone with a guide on how to build a DFU updatable custom network application for nrf5340, with sysbuild or child image would be appreciated. I am currently trying to get \nrf\samples\ipc\ipc_service working. Thank you.

First of, since there's quite a significant change between child/parent images, I recommend you to go through the sysbuild topic at our academy pages: https://academy.nordicsemi.com/courses/nrf-connect-sdk-intermediate/lessons/lesson-8-sysbuild/topic/sysbuild-explained/. This will give a breakdown of the abstraction in the sysbuild docs.

The next item I would like you to go through is the migration guides here: https://docs.nordicsemi.com/bundle/ncs-3.0.0/page/nrf/releases_and_maturity/migration_guides.html with focus on these three

• https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/releases_and_maturity/migration/migration_sysbuild.html 
• https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/releases_and_maturity/migration/migration_hwmv2.html 
• https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/releases_and_maturity/migration/migration_guide_2.7.html 

Kind regards,
Andreas

[dev_j]

Hi AHaug ,

Thank you for your reply. I am more familiar with how child image/parent work and that's where I will focus my question. I can build the nrf5340 network core application that produce signed_by_b0_app.hex and net_core_app_moved_test_update.hex that I use for updating  the firmware. The issue is these are only produced when I have the CONFIG_BOARD_NRF5340DK_NRF5340_CPUNET in prj.conf and this configuration enables the default ncs\v2.6.1\nrf\samples\nrf5340\empty_net_core, which means my network core code lives inside the SDK. I would like to produce a files to update network core firmware without putiing the network core code in the ncs\v2.6.1\nrf\samples\nrf5340\empty_net_core. For example when I use the \nrf\samples\ipc\ipc_service project, I am planning to use the \nrf\samples\ipc\ipc_service\remote as my network code. When I build it I only get merged_remote.hex, app.hex, zephyr.hex. None of these files are working for updating the network firmware. I had already gone through the links provided above.