I have an nRF5- DK and I'm following this tutorial. I loaded the softdevice, I can compile, I can load the flash, I can see the output in Termite, I can change the code to print different information to termite. That all works. But, when I use the nRF Toolbox app on iOS to connect, there is a device called "Nordic_Prox" NOT a device called "Nordic_UART". If I attempt to connect to "Nordic_Prox" the program crashes (eg the LED stops flashing and no connection is made).
I believe the name "Nordic_Prox" comes from the fact that I had previously flashed the Proximity_Demo hex file which uses the name "Nordic_Prox". The Proximity_Demo file worked, so I doubt there is a hardware problem.
I had very similar, possibly identical, problems when using the mbed compiler. I'm not sure if it is related or not.