According to the code of adafruit, P11 is for DFU and P12 is for FRST. I’ve checked the layout of 5010. They are like this. P11 is for UART CTS of BG96, P12 is for LED.
But in our demo, we do not use these two pin. They should be default state. According to nordic SDK, they should be:
So if you want to use DFU funtion, I advise you change the Pin num in code of adafruit, point to the rest pin for user. Like IO1 to IO4. But remember, the four pins is useful unless input 3V3 to Vref closed IO1~IO4.
Below is the circuit diagram of 5010.
And other details