I have an nrf52840 dongle. I can enter into DFU mode and the nRF programmer application recognizes it and shows the memory layout.
When I copy sniffer_pca10056_129d2b3.hex into the hex file area it shows up. But the Write button on the right never is enabled.
The layout explorer shows that the sniffer hex is located from 0x0 - 0x5328, I'm guessing this is the issue, but I am not sure on how to tell the programmer to program the sniffer file to a different address.