Cannot connect nRF52840DK to PC anymore

RE: Cannot connect nRF52840DK to PC anymore

RF_Eng — Tue, 31 Mar 2026 20:06:49 GMT

Priyanka Just wanted to check, if there are any updates? Would I be able to use this board again, as I need it urgently in the next days?

RE: Cannot connect nRF52840DK to PC anymore

RF_Eng — Wed, 25 Mar 2026 09:16:22 GMT

Thanks a lot

RE: Cannot connect nRF52840DK to PC anymore

Priyanka — Wed, 25 Mar 2026 08:48:48 GMT

Hi,

Then it should be an issue with the debugger. I will report this internally and will keep you updated.

-Priyanka

RE: Cannot connect nRF52840DK to PC anymore

RF_Eng — Wed, 25 Mar 2026 08:30:22 GMT

I have flashed the BLE Uart Service (from the examples) without any modifications.
I connected the cable to USB J3, the BLE works and LED1 flash as usual, but still can't see the COM port on the PC. No changes in the device manager when I connect it.

RE: Cannot connect nRF52840DK to PC anymore

Priyanka — Wed, 25 Mar 2026 08:04:54 GMT

WHat was the firmware that you flasehd onto the DK? If it uses a USB, then you should see a new USB device pop up on the PC (COM port). But if the firmware you flashed did not use USB, then you will still not see anything, but the BLE should work and the LED should work as usual.

-Priyanka

RE: Cannot connect nRF52840DK to PC anymore

RF_Eng — Tue, 24 Mar 2026 15:10:34 GMT

Thanks for the suggestion!
Sure, But what should I observe when I connect the other USB on the board?

RE: Cannot connect nRF52840DK to PC anymore

Priyanka — Tue, 24 Mar 2026 14:53:05 GMT

Hi,

Could you try connecting to the other USB on the board? This can help confirm if it's the debug chip's issue.

-Priyanka

RE: Cannot connect nRF52840DK to PC anymore

RF_Eng — Mon, 23 Mar 2026 10:14:08 GMT

Hi Priyanka,

Nothing happens when I hold the reset button and restart the board.

As far as I saw on the website, nrfjprog are archived, so I tried the alternative nrfutil, but this didn't detect the board.

Starting the programmer tool also didn't detect the device and didn't prompt re-programming.

I am not sure what could have happened to the board, as I just recently bought it and didn't try anything except some of the basic applications and always programming using visual studio code with the nrf plugin/extension. Is there a way to regain access to the board?

RE: Cannot connect nRF52840DK to PC anymore

Priyanka — Mon, 23 Mar 2026 09:43:35 GMT

Hi,

This could be that the interface MCU has become faulty.
What do you get when you try this?

[quote user=""]Holding the reset button, while restarting the board also doesn't help.[/quote]

Did you try nrfjprog device recover? PLease install the nRF Command Line Tools and try this.

Could you try to open the Programmer app in the nRF Connect for Desktop application, and see if you are prompted to re-program the debug chip?

-Priyanka