NRF5340 Network Core USB DFU with dfu-util

RE: NRF5340 Network Core USB DFU with dfu-util

MKir — Wed, 17 Sep 2025 10:33:06 GMT

Hello,

Thanks a lot. I got it to work with dual slot setup, after debugging the single slot setup which I understood here to be possible: https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/app_dev/device_guides/nrf53/serial_recovery.html

I did not manage and I believe the documentation is misleading in this respect. I've opened Documentation page for NRF5340 serial recovery.

RE: NRF5340 Network Core USB DFU with dfu-util

AHaug — Tue, 16 Sep 2025 08:29:47 GMT

Hi,

Good thing you asked. I've not tested this myself, but afaik it is possible to do since ~NCS v2.7.0 according to https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/app_dev/device_guides/nrf53/serial_recovery.html. I had a look through https://academy.nordicsemi.com/courses/nrf-connect-sdk-intermediate/lessons/lesson-9-bootloaders-and-dfu-fota/topic/exercise-1-dfu-over-uart/ to see if it was covered here, but only serial recovery of the application is covered there.

Let me know if the serial recovery docs linked above is enough for you to validate if this solution can work for you.

One of the reasons for why we recommend simultaneous DFU of both cores on the 5340 is in case you make some changes that may break the interface between the app and net-core. For instance let's say that you first do an update of the network core over BLE where the interface has changed. When you reboot after the swap you may be left in a situation where the app core does not know how to communicate with the netcore and thus you don't have BLE available to revert/update the app core and you will be forced to either reprogram or do serial recovery. Simultaneous OTA ensures that the appcore is built to be able to communicate with the netcore and you have the option to revert the update since you do dual bank slot.

Kind regards,
Andreas

RE: NRF5340 Network Core USB DFU with dfu-util

MKir — Mon, 15 Sep 2025 14:57:41 GMT

Thanks Andreas,

I see that simultaneous multi-image update only works with a dual-slot configuration. Is it possible to have non-simultaneous update of the network core with a single slot configuration (CONFIG_SINGLE_APPLICATION_SLOT /SB_CONFIG_MCUBOOT_MODE_SINGLE_APP) with serial recovery / mcumgr?

I have seen a comment here from 3 years ago that says no.

RE: NRF5340 Network Core USB DFU with dfu-util

AHaug — Wed, 10 Sep 2025 12:22:08 GMT

Hello,

[quote user=""]We want to implement the update in the bootloader to remove the requirement for external flash for the second firmware slot.[/quote]

I understand this need and requirement and it is a feature that's in the making for NCS.

As briefly mentioned in https://www.linkedin.com/posts/nordic-semiconductor_introducing-the-nrf-connect-sdk-bare-metal-activity-7366726990546104321-03xG?utm_source=share&utm_medium=member_desktop&rcm=ACoAACBLfxoBqFOYLbAjars5fOj1EIXIvvDBdiM (and maybe in https://webinars.nordicsemi.com/events/34049549399?n=Introducing%20nRF%20Connect%20SDK%20Bare%20Metal%20option&event_id=34049549399&hsLang=en), the single bank OTA feature is something that we've introduced in NCS Bare Metal (for 54L15 only), and that will make its way into NCS in the future.

This does however not help you right now as it's not supported yet.

[quote user=""]I have seen a similar issue, but that discusses the possibility of simultaneous update and does not show how the network image can be downloaded: devzone.nordicsemi.com/.../use-dfu-util-to-perform-multi-image-dfu-from-application[/quote]

As I briefly mentioned in the ticket you refer to, dfu-util is not supported, so any implementation you choose to use will have to be a proprietary solution that you adapt yourself. For the nRF5340 I would recommend you to stick to the supported methods for DFU, i.e simultaneous update of net and app-core as well as the supported tools

Kind regards,
Andreas