NRF5340: FW OTA

[Jason]

Hi:

I am working on the NRF5340 FW OTA.

By reading this document Secure bootloader chain, I think our FW architecture should use MCUboot as the upgradable second-stage bootloader as below.

As I know, the default MCU Boot is not able to receive the FW, just swap the FW. I have questions as below:

1. how to custom the MCUBoot to be able to receive the FW by BLE like the application?  because if the application is corrupted(e,g, overwrites parts of the application firmware image) somehow by the bug, the device should stay in the MCU boot and be able to recover the application by BLE.  Is there any sample code or document for this?

2. if question 1 is not a recommended method, what is the recommended method?

Thanks!

[Jason]

Hi,

AHaug said:

Could you elaborate on why serial recovery is impossible?

I thought the serial recovery only supported UART, so it is impossible for the user to recover the device because they don't have USB-to-UART hardware. now I find the serial recovery also supports USB CDC, this may be an option. But the best way is the recovery mode to support BLE. so that is very easy for the user to recover the crashed device. (we have a smartphone  APP for our product).

[AHaug]

Thank you for elaborating.

Yes, USB CDC could be an option for you in that case. I would recommend you to have a look at the serial recovery samples in this repository written by a colleague of mine. (The samples here are free for you to use in your applications, but do note that they are unofficial and have not been tested by us to be put into the official SDK, so the responsibility is on you if you use them. Nonetheless, they are great at illustrating how to do that specific thing they are written to do.)

Full link: https://github.com/hellesvik-nordic/samples_for_nrf_connect_sdk/tree/main/bootloader_samples

As always, please feel free to ask additional questions related to the topic if anything is left unclear

Kind regards,
Andreas

[Jason]

Hi AHaug,

No more questions, Thanks for your support.