due to unknown reasons, my nrf52840-DK (1.0.0) didn't come back up after flashing software to it. Means the LED that usually turns on when you power it up remains off. I started the board in "flash interface firmware" mode which works but I can't find the JLINK firmware on either Nordic or Segger websites. I'm pretty sure it was available for the older nrf51-dk.
I flashed mbed's dap-link but that, of course, doesn't work together with the NRF Connect Programmer. Anybody who could post the link to the interface firmware here?
Ah - update through J-Link configurator doesn't work either as a Jlink firmware needs to be working in the first place. Couldn't spot the firmware in the Windows Jlink Directory either.
Have you tried turning off the dev kit & holding in the Reset button on the DK while powering it back on. You should then see the device appear as a Bootloader drive. You should then be able to drag & drop this file (i.e. interface MCU FW) to the DK. Afterwards, power cycle the DK & you should see the DK work as a JLINK device again.
Thanks Bjorn for pointing me to the Download section. I've been there yesterday but must have overseen the last item which contains the interface firmware. My board is working again.