Adding BLE DFU Support on Custom Board with nRF5340 + nRF7002 (SDK v2.8.0)

RE: Adding BLE DFU Support on Custom Board with nRF5340 + nRF7002 (SDK v2.8.0)

Hung Bui — Thu, 15 May 2025 11:15:07 GMT

Hi,
If you disable SB_CONFIG_BOOTLOADER_MCUBOOT , the DFU option is removed. This may explain why you don't see flash overflow.

Yes if you use external flash it will free up half of the internal flash (that used for receiving new image) for the application. So you will most likely have enough flash to fit MCUBoot and your application.

RE: Adding BLE DFU Support on Custom Board with nRF5340 + nRF7002 (SDK v2.8.0)

ozoz05 — Thu, 15 May 2025 02:36:25 GMT

This is the size shown when the project is built.
(I disabled SB_CONFIG_BOOTLOADER_MCUBOOT=y in sysbuild.conf because enabling it caused a flash overflow error.)
In that case, it seems that using external flash is essential for implementing OTA reliably.
If I use external flash, will the flash overflow error disappear when SB_CONFIG_BOOTLOADER_MCUBOOT=y is enabled?

RE: Adding BLE DFU Support on Custom Board with nRF5340 + nRF7002 (SDK v2.8.0)

Hung Bui — Wed, 14 May 2025 08:08:48 GMT

Hi,

What's the size of your application ?

The reason that the external flash is by default required is that in many case if you want to update the network core it's not possible to do that with the internal flash as you will not have enough spare space to receive both the application core image and the network core image.

It's possible to do DFU with the internal flash but then you have quite limited flash size and you can only update the application core which is not ideal.

RE: Adding BLE DFU Support on Custom Board with nRF5340 + nRF7002 (SDK v2.8.0)

ozoz05 — Wed, 14 May 2025 06:22:41 GMT

Hello,
In the Nordic Academy lessons, DFU is set up by default using external flash.
Is it possible to perform OTA using Wi-Fi or DFU using BLE without external flash?

Reference example link:
abluethinginthecloud/nrf7002-bsd-sockets-example: nRF7002 DK TCP and UDP BSD Sockets example

In the image above, I would like to ask:
If the gray space in the application core is small, does that mean DFU without external flash is not possible?

The partition layout was slightly modified from the 7002 DK default.

Adding SB_CONFIG_BOOTLOADER_MCUBOOT=y to sysbuild.conf results in a memory overflow error.

RE: Adding BLE DFU Support on Custom Board with nRF5340 + nRF7002 (SDK v2.8.0)

Hung Bui — Tue, 13 May 2025 11:51:53 GMT

Hi 오지환,

I'm not aware of "those examples rely on specific hardware configurations like LEDs, buttons, and external memory present on the DK." could you point me to which examples you are looking at ?

I would suggest to take a look at this Nordic Academy lesson https://academy.nordicsemi.com/courses/nrf-connect-sdk-intermediate/lessons/lesson-9-bootloaders-and-dfu-fota/topic/exercise-5-fota-over-bluetooth-low-energy/

I will give you the detailed instruction on how to implement BLE DFU in your application.