All credit goes to mame82 (https://twitter.com/mame82)
I'm using the MakerDiary nRF52840 MDK USB Dongle:
The repo with the firmware is located here:
To install the firmware onto the nRF52840, you need the Nordic Semiconductor nRF Connect for Desktop:
Once downloaded and installed, install the "Programmer" under Add/remove apps.
After the Programmer is installed, hold down the button on the dongle and insert into the USB port. The dongle should enter flashing mode with a solid green and slowly flashing red light. If the device doesn't appear in the drop down, close and restart the Programmer app.
Once selected, add the logitacker_mdk_dongle.hex and select Write.
The device will not show up properly in the programmer after it is flashed but you should see the new firmware version in the selection pane.
Use the following settings for putty:
Once connected, you should be able to connect and see your device.
So there you have it! You are now on your way to see what your Logitech devices are doing. Remember to be responsible and don’t do anything illegal.