Bricked nrf52840 Dongle

RE: Bricked nrf52840 Dongle

Hung Bui — Tue, 27 Jan 2026 11:48:33 GMT

Hi,

This is very old thread. I would suggest you to create a new ticket for this.
I would suggest to use a nRF52840 DK to get started instead of using the dongle. The dongle is not a platform for developing application.

RE: Bricked nrf52840 Dongle

bricked — Sun, 11 Jan 2026 17:51:40 GMT

OK, so is there some script already that actually results in a Thread 1.3 (or whatever is newest) firmware that I can flash in the same way for any operating system (I can port it to mine)? So, last time I depended on you providing a .hex file.

I want to add some extra Thread 1.3 devices, but AFAIK your 5008.nrf52840_dongle_thread_coprocessor.hex is already too old.

RE: Bricked nrf52840 Dongle

bricked — Tue, 03 Jun 2025 17:37:26 GMT

I flashed your latest coprocessor. Now, it works:

lsusb  | grep -o 'ASA Thread.*'
ASA Thread Co-Processor

OK, I managed to get OTBR working (and without root privileges as well).

RE: Bricked nrf52840 Dongle

bricked — Fri, 30 May 2025 17:21:26 GMT

It started dimming again and listed under lsusb again. So, hardware saved and thank you for that. 💯

The last thing I want is a graphical environment, unless they work better than a command line interface (and unfortunately, all of your tools are npm thrash (_Nobody_ in the NixOS community likes it when they need to patchelf all your tools to make them work)).

A decent developer experience would be literally nothing more than the below (so, not even having to care where the URL of your SDK is). I don't really get why for this particular flow (that is, just people wanting to _use_ your chips instead of developing for them) you don't optimize. Obviously, if I ever want to really develop for your chips and have some custom application, then I might want to actually have a git checkout of your repo in a place on my system I want to know about, but otherwise, just hide all those unnecessary details (that's called _abstraction_).

#!/bin/sh
wget https://yoursdk.com/default.nix
nix-shell
# screen shows which applications are available for direct flashing: 
# 1. RCP
# 2. blinking app
# usage flash <number> (e.g. flash 1 for RCP)
flash 1 # wait a few seconds and it works.

Perhaps I am underestimating the amount of products with your chips in it, but writing such a shell script would take anyone familiar with all your tooling perhaps 30 minutes.

RE: Bricked nrf52840 Dongle

Sigurd Hellesvik — Fri, 30 May 2025 11:50:53 GMT

Uploading files again here since they prev seems wrong:

devzone.nordicsemi.com/.../5008.nrf52840_5F00_dongle_5F00_thread_5F00_coprocessor.hex

devzone.nordicsemi.com/.../2845.nrf52840dongle_5F00_blinky.hex

RE: Bricked nrf52840 Dongle

Sigurd Hellesvik — Fri, 30 May 2025 11:48:12 GMT

[quote user=""]How do I recover to factory settings (assuming I have little to no tools right now, but I can buy tools)? I pressed the white button (there are no other buttons visible) in an attempt to reset to factory settings. [/quote]

You got two options:

Reprogramming the Dongle using a debugger. This is the "nuclear option", which requires you to connect the Dongle to the DK.

However, I think you missed a button, so you should still be able to put the Dongle into DFU mode and then program it again.

In addition from the button you see, there is a sideways button:

Press this (from the arrow direction) when the Dongle is plugged in. The Dongle should now enter programming(DFU) mode, and the LED should tart blinking(fading) red.

[quote user=""]Overall, I consider it a _horrible_ developer experience for trying to do something which should have been simple (adding an OBTR to the network). [/quote]

If you want a more graphical method for programming the Dongle, try to download nRF Connect for Desktop, open the Programmer app, select the hex and then press "program" when the dongle is in programming mode.

[quote user=""]What do I need to flash Openthread RCP on it such that it *does* work? [/quote]

"Just program the hex file" is the short answer. While this is not helpful as such, at least you get confirmed that the hex should work as-is.

The long answer goes as this:

Looks like you follow the OpenThread guide. This is OpenThread, and not Nordic Semiconductor.
We do have our own Thread Coprocessor code in our SDK. Yes, these two should be the same, but we can only promise things for our version, as this is the one we run testing on.
See Thread: Co-processor.

However, installing the SDK is a bit of work, but if you intend to develop with the nRF later, you might as well install it now. To get started, I recommend https://academy.nordicsemi.com/.

If not, here is a hex file that I just built (and did not test) that you can try:

devzone.nordicsemi.com/.../0005.nrf52840_5F00_dongle_5F00_thread_5F00_coprocessor.hex

I can test it next week if needed, but I built it as the tests do, so it should work.

PS: Here is also blinky, so that you can verify that the programming works for anything:

devzone.nordicsemi.com/.../7851.nrf52840dongle_5F00_blinky.hex

[quote user=""]Why is it even possible to have a successful flash that bricks the device in the first place? E.g. why is there no simulation of some kind to make sure the resulting flashed device does something useful? [/quote]

I assume that the other button answers this.

[quote user=""]If I need to buy something to make this work, what? [/quote]

Generally no. At worst a DK, but looks like you already have that. Maybe a cable, but lets get to that if the above did not work.

Regards,
Sigurd Hellesvik

RE: Bricked nrf52840 Dongle

bricked — Thu, 29 May 2025 16:06:52 GMT

I procured a nrf52840-dk and a new nrf52840 as well, but even with those the questions largely remain open. Also, I absolutely do not want to brick anything else.