Nordic nRF-52840DK J-Link not working and cannot get into Bootloader Mode

[wiktor]

Hey all,

Have just been messing around with the board, everything was working fine until I tried to follow this guide to install CircuitPython onto the nRF. I got it into bootloader mode and dragged the .bin file across. 

Now I know this is an Adafruit firmware, and that it's not supported by Nordic but I highly doubt this issue is exclusive to Circuitpython but more so with breaking J-Link in general. The blinky app that was flashed on it before is still working, but resetting it and trying to enter bootloader mode isn't working anymore. Windows and Linux both aren't seeing the device after plugging into it using USB either. Is there a way to revert back to factory settings and/or re-flashing J-link onto it? 

Many thanks,

[Amanda Hsieh]

Hi, 

Please check the DK with this post.

-Amanda H.

[wiktor]

Hi Amanda,

I actually ran through the steps in that post before posting here as a last resort.

• Does the device show up in Device Manager on your computer? Please try to connect and disconnect the kit a few times. It might show up with unexpected names.
  • The device does not show up in device manager, no matter how I turn it on and what USB port I use.

• Have you tried a different USB cable? Faulty cables are surprisingly often the problem.
  • Three different cables, all work with colleagues boards, not with mine.

• Have you tried using a different computer? If it works on a different computer we know that the kit is not broken and that it is probably a driver issue.
  • Different PC's do not solve the issue.

• Have you tried to press the IF BOOT/RESET button while power cycling the kit? It should then show up as a Removable Storage Device named "BOOTLOADER". Then you can drag-and-drop the J-LINK interface MCU firmware found here (v170724) onto the storage device to reprogram the JLINK firmware.
  • No matter how I plug it in, bootloader/non-bootloader, the PC does not recognise the board.

• Have you measured the supply voltage on the kit? It should be somewhere between 2.8V-3.3V. If it isn't, then the hardware is probably broken.
  • I get a nice 3.3v VDD, same as my colleagues' board.

• Have you made sure that you are using the latest J-Link driver version? https://www.segger.com/downloads/jlink
  • Yes, everything is updated.

• Have you tried this guide? https://devzone.nordicsemi.com/blogs/...
  • I Have run through this guide and none of the CLI software could pick up the board - it was as if it was not plugged in at all.

Thanks for the reply, any help on this would be appreciated.