Using Serial recovery with the NRF5340

RE: Using Serial recovery with the NRF5340

runsiv — Fri, 10 May 2024 11:11:52 GMT

In general I don't think it would lead anywhere to create a custom HCI command since it would only affect the network core and not reset the application core for the 5340. I presume you are using HCI_USB, and there is a PR for adding a warning regarding it. I think the best solution would be to either forward a GPIO to the network core that you connect to the reset pin, so you can trigger a reset for application core and enter bootloader option.

Another alternative would be to configure the application so that it enter bootloader mode for a few seconds every time you reboot your device.

I would also suggest looking into HCI_UART over usb then using hci_usb. To cite a coworker "I get the impression that hci over usb as a transport layer is slightly unstable by design; for simple use cases where transfer is not stressed then hci_usb is functional, but for stability you should use uart or spi as hci transport. It seems as most vendors use uart hci transport due to this, e.g. in phones, laptops etc. We plan to add a disclaimer to the hci_usb sample. A suggested workaround is to use compile hci_uart with the cdc uart driver instead (if you need to use usb, and cant use uart or spi directly)."

Regards

Runar

RE: Using Serial recovery with the NRF5340

Utsav R Shah — Fri, 10 May 2024 07:55:05 GMT

Thank you so much runsiv for the suggestion. I will definately go through the course material to know more about DFU.

I had gone through some applications on serial recovery and was successfully able to do a firmware update on my DK board.

I wish to ask one thing which is about creating a custom HCI command to reset the board in case a firmware update has to be done in runtime. I would be using the Custom BL5340 board that does not have support for any button reset and it may not be possible for me to restart the entire system to go into recovery mode.

How can I create a custom HCI command that I can execute at runtime so that the board goes into recovery mode?

RE: Using Serial recovery with the NRF5340

runsiv — Fri, 10 May 2024 07:18:31 GMT

Hi Utsav

I think my best recommendation would be to go through our lesson on Bootloaders and DFU in the NCS Intermediate course. It gives a very good understand how DFU and how everything fits together.

Regards

Runar