nrf52840 not recognized after flashing using nrfutil

[jdamian]

Apologies if this has been asked a bunch of times but none of the posts I ran into were helpful. This is my first time working with a dongle of this nature so apologies if I'm making any obvious mistakes. My nrf52840 was working just fine but I needed to flash it with a different firmware for testing purposes. I ran this command ./nrfutil dfu usb-serial -p <port> -pkg <path_to_zip>  on a Linux virtual machine and the device was disconnected automatically from the VM. When I reconnected it I was able to run the same command without any errors but after the process was completed the dongle's green light has been non-stop blinking and my device is neither recognized by the nrfconnect software or nrfjprog (nothing is shown when I run nrfjprog -i). I tried sending .hex files via the nrfconnect desktop app, recovering using nrfjprog, pressing the reset button multiple times and re-flashing using nrfutil with no success.The picture below displays what I currently see when I attempt to connect the device to the nrfconnect desktop software and I attempt to add a .hex file. Any advice is greatly appreciated.  

 

Thanks!

[Edvin]

Hello,

Does the red LED start flashing (breathing) when you press the reset button on the dongle while it is powered? Note that the reset button is the button next to the big white button.

 

and my device is neither recognized by the nrfconnect software or nrfjprog (nothing is shown when I run nrfjprog -i).

 That will always be the case with the dongle, because it doesn't have a debugger.

 

recovering using nrfjprog

 That will not work either. In fact, nrfjprog doesn't work on the dongle, as it doesn't have a debugger.

 

pressing the reset button multiple times and re-flashing using nrfutil with no success

 Does this mean that it starts blinking red when you press the button?

Note: After you program your custom application to the nRF52840 dongle, it will only be recognized by a computer if that application uses the USB peripheral. If not, the USB pins on the dongle are not connected to anything.

Best regards,

Edvin

[jdamian]

Hi Edvin, thanks for clarifying. It seems like resetting the dongle again did the trick, not sure why it wasn't working when I first tried it. Thanks!