After the Bluetooth mesh dfu is completed, the distribution network information of the node is cleared

[llly]

I have implemented DFU functionality in my Bluetooth mesh project and used device A as the distributor and device B as the node to be updated. I have already configured both devices and they can communicate with each other. Then I use the distributor to send new firmware to the node. After the node firmware is successfully updated, the original distribution network information of the node is cleared. At this point, the distributor and the node cannot communicate and need to manually reconfigure the distribution network. How can the original distribution network data be retained during DFU updates?

[Hung Bui]

Hi Illy, 
Please describe how you did the DFU update ? 
If you use the phone to send the image please check this similar ticket : BLE Mesh NCS: Provisioned data lost after DFU 

[llly]

Hi

There are two examples in NCS: Bluetooth mesh distributor and Bluetooth mesh target. I am using these two examples to test the performance of mesh DFU.

After downloading these two examples to two devices, the first step is to use a mobile phone to send the new firmware of the node to be updated (i.e. the device running the Bluetooth mesh target) to the distributor, and then control the distributor to send the new firmware received from the mobile phone to the node to be updated through a shell command. In other words, the node to be updated will not directly communicate with the mobile phone, but will forward the new firmware from the mobile phone to the node to be updated through the distributor. Therefore, the erase option on the mobile phone has no effect (the erase nvs partition option is turned off by default during updates, and can only be manually enabled to erase nvs partitions, but I have never enabled it)

[llly]

The reason for the two hash values being different has also been identified. It is because I used a vendor customized model in my project, but there is still an issue at this time. I have changed BT_MESH_ELEM(0, models, vendor_models) to BT_MESH_ELEM(0, models,  BT_MESH_MODEL_NONE)in my project to cancelled the vendor custom model. At this time, the hash value in the upgrade package is consistent with the calculated hash value

And the two hash values after adding the manufacturer's custom model are the same as those in my previous reply

[Hung Bui]

Hi Illy, 

Please clarify, after you managed to get the same metadata hash, do you still have the issue of the device unprovisioning itself ? 

[llly]

Hi

When the hash is the same, there will be no problem of becoming an unprovisioning device

The problem to be solved now is that after adding the manufacturer's custom model, the hash value in the automatically generated upgrade package is different from the calculated hash value

[llly]

Hi

https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/releases_and_maturity/known_issues.html#bluetooth_mesh

I found this known issue on my search, but I am not sure if it is related to the problem I encountered

[llly]

Good news. I have found a solution now, which is to manually change the hash value in the upgrade package to the correct hash value, then upload the modified upgrade package to the distributor, and then perform dfu normally. At this point, the img_effect will be BT_MESH_DFU_EFFECT_NONE, and the node upgrade will not become an unprovisioning device after completion

But this is too troublesome, so this problem still needs to be solved