Question about Bluetooth OTA and UART DFU with nRF54L05

RE: Question about Bluetooth OTA and UART DFU with nRF54L05

Kenta — Tue, 19 Aug 2025 05:21:09 GMT

Hello Einar.
I'm sorry for the delayed response as it was summer vacation.

I understand from this thread that Bluetooth OTA for nRF54L05 seems to be challenging in terms of capacity.
devzone.nordicsemi.com/.../nrf54l05-cannot-ota

I tried the UART Serial DFU method referenced in this thread, and it worked successfully.
devzone.nordicsemi.com/.../mcuboot-won-t-boot-into-serial-recovery-mode-by-using-retained-memory

For now, I have confirmed that UART DFU (Single slot) is possible for the nRF54L05, so I will share this information with the my team.

This issue has been resolved for now, so this ticket can be closed.
Best regards.

RE: Question about Bluetooth OTA and UART DFU with nRF54L05

Einar Thorsrud — Thu, 07 Aug 2025 13:05:39 GMT

Hi,

You are close to using the available RRAM (at 90.74%), so it may be that wil need external flash. But it is not strictly needed if you have a small application, and here it does fit. Unless you need to fit a larger application I would start by debugging on the nRF side to see what is going wrong, as this shold work.

That said, if you need a larger application slot you need external flash. You can refer to the smp_svr sample with the nrf54l15dk_nrf54l15_cpuapp_ext_flash.overlay for how to do that. This is for nRF54L15 so sizes need adjusting, but appart from that the device and how it is used is identical.