Programming the nRF52840 MDK USB Dongle

[capablegh]

Hello.

I have a nRF52840 MDK USB Dongle that I purchased at least 3+ years ago. I am following the instructions as posted on https://wiki.makerdiary.com/nrf52840-mdk-usb-dongle/guides/ncs/samples/hello_world/. To program the board/dongle I press the only button on the it, then power it on. The green LED to the immediate left/closest to the USB connector turns on, but the red LED on the right and bit farther is off. I release the button, and I see the red LED start to blink. At this time I see /dev/ttyACM0 get created, but no USB MSD is visible (per /proc/partitions).

With this I cannot copy the 'zephyr.hex' file to the MSD. What am I missing? What do I need to be able to program the Zephyr image?

To try another approach that is not described in the above, but is in Nordic's tools:

nrfutil device list
WARNING: JLinkARM DLL not found. SEGGER J-Link devices will not be recognized correctly, and J-Link operations will not be available. Install J-Link from https://www.segger.com/downloads/jlink/.

E41334F9060E
product Open DFU Bootloader
ports /dev/ttyACM0
traits nordicDfu, nordicUsb, serialPorts, usb

Found 1 supported device(s)

So I tried the following and it fails

nrfutil device program --serial-number E41334F906XX --firmware zephyr.hex
WARNING: JLinkARM DLL not found. SEGGER J-Link devices will not be recognized correctly, and J-Link operations will not be available. Install J-Link from https://www.segger.com/downloads/jlink/.

[00:00:00] ------ 0% [E41334F9060E] Failed, [sdfu] firmware file extension .he
Error: One or more program tasks failed

So it seems the UF2 bootloader is not on the board, but the Nordic's DFU is. At least the board gets recognized by nrfutil. If this is the command to be used, what am I missing? What do I need to get it to work?

[capablegh]

The Zephyr example https://docs.zephyrproject.org/latest/boards/arm/nrf52840dongle_nrf52840/doc/index.html with the instructions to create the DFU ZIP file and to program it works. The same should apply for Mbed.