After placing the secondary slot in the external flash, Bluetooth DFU cannot be performed

[llly]

I used the NUS example and enabled the Bluetooth DFU function. By default, the first and second firmware slots are both placed in the internal flash. At this time, the Bluetooth DFU function is normal.But when I put the secondary slot in the external flash, the Bluetooth DFU will fail.

Selecting firmware in the nrf connect app and clicking start upload will immediately fail, and the device will output the log in the red box below.

[llly]

I encountered this problem on 54l15dk, and then I retested it on 52840dk, this problem would not occur on 52840dk

[AHaug]

Hello,

Could you share the external flash configuration you've set up? For the nRF54L15 you will have to use SPI, whereas for 52840DK you can use both SPI and QSPI. I suspect that since it works for the 52840dk it is due to your project having QSPI configured. I suspect that this might be the fault https://academy.nordicsemi.com/courses/nrf-connect-sdk-intermediate/lessons/lesson-9-bootloaders-and-dfu-fota/topic/exercise-3-dfu-with-external-flash/ 

Kind regards,
Andreas