Mesh DFU Failed to establish connection

[Jeffe]

Hi, recently I am been consistently getting the same issue as this post, despite having successful performed the Mesh DFU in the past and with the example code:  NRF MESH SDK5 DFU issue "Failed to upgrade target. Error is: Failed to establish connection" 

I suspect my issue might be the same as the person in this post, however, the person did not give much details.

Thanks in advance

[Edvin]

Hello,

What kind of error do you get? And what did you try to do? You say that you succeeded running Mesh DFU in the past with the example code. What are you doing now? Are you still running the same example code? Did you change SDK version? Did you try to integrate DFU into a custom project? Some more details would be nice.

Best regards,

Edvin

[Jeffe]

An update on my progress:

So far no luck actually. The same computer where I got the DFU working now gives me either the same issue as above, or the "Lost connection in the setup phase" error. Are there any pointers to help me debug this issue. Could my issue be related to my link to the other thread?

[Edvin]

I wouldn't worry to much about the thread that you linked to. 

Can you please show me what it looks like when you try to perform the DFU?

And until you get it working, can you please try to follow this guide using an unmodified mesh SDK and an unmodified nRF5 SDK with the unmodified DFU example?

Does this unmodified example work? If not, where does the behavior differ from the guide?

BR,

Edvin

[Jeffe]

Hi, 

When I tried performing the DFU update using the example and unmodified SDK, I still got the same issue -- however -- it was successful when I stopped using the same DK board. I think something was wrong with that specific DK board I was using.

Later, I decided to reprogram the interface MCU on the DK board in question using this link: https://infocenter.nordicsemi.com/index.jsp?topic=%2Fug_nrf52832_dk%2FUG%2Fnrf52_DK%2Fint_mcu_firmw.html, and reprogrammed the interface Jlink programmer chip with the firmware here: https://www.nordicsemi.com/Products/Development-hardware/nRF52840-DK/Download?lang=en#infotabs, and that DK in question started working properly with the DFU again.

I honestly think that the original thread I linked to was correct in their diagnosis of the issues. Perhaps there was some obscure bug in the interface MCU with the virtual COM port's flow control. I have tested UART examples and run many programs that use UART on the nrf52840 DK but none of them ever used flow control, but the mesh DFU serial module does use flow control. Additionally, since the issue seemed to go away after I set the interface MCU into bootloader mode and reprogrammed it, I'm inclinced to believe that it was indeed some flow control issue with the interface MCU.

I will do more further tests with the Mesh DFU, since I'm not 100% sure yet, I will keep this ticket updated. Thank you for your help. 

[Jeffe]

I haven't had this issue ever since I have reprogrammed the interface Jlink programmer chip on the nrf52840 DK. I think my issue is solved