MCUboot’s serial recovery of the networking core image does not on nRF5340 DK

[lincoln-lu]

I am building the sample project C:\ncs\v2.5.0\nrf\samples\bluetooth\peripheral_uart, which supports MCUboot’s serial recovery of the networking core image on nRF5340DK.

As the README said,

"MCUboot with serial recovery of the networking core image

=========================================================

For the ``nrf5340dk_nrf5340_cpuapp``, it is possible to enable serial recovery of the network core while multi-image update is not enabled in the MCUboot.

See :ref:`peripheral_uart_sample_activating_variants` for details on how to build the sample with this feature using the :file:`nrf5340dk_app_sr_net.conf` and :file:`nrf5340dk_mcuboot_sr_net.conf` files."

1. I did not change any code, and here is the west build command I used to build the project while enabling serial recovery of the network :

west build -p -b nrf5340dk_nrf5340_cpuapp -- -DOVERLAY_CONFIG="nrf5340dk_app_sr_net.conf" -Dmcuboot_OVERLAY_CONFIG="${PWD}/nrf5340dk_mcuboot_sr_net.conf" > build.log 2>&1

2. I flashed the merged_domains.hex into 5340DK by using "west flash" command.

3. I put the DK in serial recover mode by holding button1 of 5340DK when reseting it, and I sent below Mcumgr cli commands to upload net core update bin file and reset it,

PS C:\ncs\v2.5.0\nrf\samples\bluetooth\peripheral_uart> mcumgr conn add testDK type="serial" connstring="COM88,baud=115200,mtu=512"      
Connection profile testDK successfully added

PS C:\ncs\v2.5.0\nrf\samples\bluetooth\peripheral_uart> mcumgr -c testDK image list
Images:
 image=0 slot=0
    version: 2.5.0
    bootable: false
    flags:
    hash: e8523a8b5b2c8811d46619741493e7e8261ea9fff5ebc59d77dfb223f15c72f6
Split status: N/A (0)

PS C:\ncs\v2.5.0\nrf\samples\bluetooth\peripheral_uart> mcumgr -c testDK image upload build/zephyr/net_core_app_update.bin
 123.43 KiB / 178.79 KiB [=======================================================================>--------------------------------]  69.03% 1.44 K 123.75 KiB / 178.79 KiB [===============================================================>----------------------------]  69.22% 1.44 KiB 178.79 KiB / 178.79 KiB [========================================================================================] 100.00% 1.23 KiB/s 2m25s
Done

PS C:\ncs\v2.5.0\nrf\samples\bluetooth\peripheral_uart> mcumgr -c testDK reset                                                           
Done

4. After reset, 5340DK seems dead, no log is printed from the UART of app core and net core.

Can you tell me what is missing in my steps above that caused this failure?

Thanks

[lincoln-lu]

I also trited the GitHub sample code "mcuboot_netcore_serial_recovery", it also failed

https://github.com/hellesvik-nordic/samples_for_nrf_connect_sdk/tree/main/bootloader_samples/serial_recovery/mcuboot_netcore_serial_recovery

[lincoln-lu]

well, I found if I added '-e -n 3' in the mcumgr command, it works.

 mcumgr -c testDK image upload -e -n 3 build/zephyr/net_core_app_update.bin

So I think the README.md on the GitHub https://github.com/hellesvik-nordic/samples_for_nrf_con should be updated for this.

[mathiaso]

Hi, Lincoln.

Thank you for reaching out regarding this. The person who has created the sample is currently away on holiday, but I've forwarded your findings to be looked at when my colleague gets back.

For further input on MCUboot, I'd recommend heading over to DevAcademy.

Best regards,
Mathias