No connection to demoboard after switch off power during mesh DFU

[JeffZ]

Hi,

I was performing a mesh DFU, using a nordic Demoboard with a serial mesh bootloader and starting DFU with nrfutil. 

The DFU starts and works good (packages are sent via mesh). I found no way how to stop it and I just switched off the power using the power switch button on the demo board. This worked for 2 times after the 3. time the demoboard is no more recognized as serial comport on the computer. 

I plugged off/on the USB cable, but this does not help. The board seems to be dead or damaged, no blinking LED etc. The board does not appear in the device manager (Windows).

Important:
This is already the 3rd board with this issue. Is there any known problem with this power switch or unplug USB cable during mesh DFU?

Thanks!

[Joakim Jakobsen]

Hi.

This has also happended to a colleague of mine.

Without knowing the exact reason behind why this is happening, he gave me a potential fix.

Have the board start up in bootloader mode (Turn the DK on with the BOOT/RESET button pressed).
Then drag and drop the Interface MCU firmware to the DK. (This can be found here: https://www.nordicsemi.com/Software-and-tools/Development-Kits/nRF52-DK/Download#infotabs)

Let me know if that fixes your issue.

Br,
Joakim