Zigbee OTA pauses after few blocks are sent

[KKoovalsky]

Hello! I have implemented a OTA cluster basing on the example: https://infocenter.nordicsemi.com/topic/sdk_tz_v4.1.0/zigbee_example_ota_client.html

I use almost exactly the same code as in the example. What I've changed is that the manufacturer ID and the image type value is different from the one in the example.

More differences are that there is also thermostat cluster along with OTA cluster implemented.

The problem is that after 2-3 firmware blocks no more blocks are requested so the OTA procedure hangs. The custom device is still operable tough.

My setup is: Zigbee coordinator based on nRF52840 Dongle, my custom device as OTA Cluster and nRF52840DK as upgrade server (running the "nrfutil dfu zigbee -f ..." command).

I attach the network dump from the sniffer: see "ZCL OTA: Image Block Response" packets - as you can see after two blocks no more are requested.ota_upgrade_bb.pcapng

During that OTA process the logs from the device look like that:

june 24 14:53:08 <info> app: DRV_ZIGBEE: Starting DFU procedure
june 24 14:53:10 <info> background_dfu: DFU trigger: init (sz=143, crc=668C29C7) image (sz=266132, crc=80CFCC6A)
june 24 14:53:10 <info> background_dfu: state=DFU_DOWNLOAD_TRIG event=DFU_EVENT_TRANSFER_COMPLETE
june 24 14:53:10 <warning> background_dfu: Installed image CRC is different

Could you help me with that issue?

[Patrick]

This may be a dumb question but are you calling app_sched_execute() in main? When I had first added OTA DFU to my project I had a similar, if not the same, issue as you've described and it turned out I had forgotten to call app_sched_execute().

[KKoovalsky]

Thank you, that actually has solved my problems.