Surprisingly, our new ordered nRF52 DK v3.0.0 boards won't work in the BLE App (nRF Connect for desktop) App. Seems related to:
"The newer devkits have hardened APPROTECT on the target device, making the debugger unable to check the firmware on the device.
You can expect this to be dealt with in a future update of the BLE App."
Source: RE: Nordic nRF52840-DK Firmware is lost after power cycle
It asks to update software, we click yes, then nothing really happens....