How to set Low Frequency oscillator(32.768khz) internal Setting

Reason : devzone.nordicsemi.com/f/nordic-q-a/54987/do-i-need-to-change-something-for-flashing-a-firmware-on-an-external-hardware-who-have-not-the-32-768-khz-xtal

Do I need to change something for flashing a firmware on an external hardware who have not the 32.768 Khz Xtal - Nordic Q&A - No

Solution : devzone.nordicsemi.com/f/nordic-q-a/33416/example-of-using-internal-oscillator-with-ble/128417#128417

Example of using internal oscillator with BLE? - Nordic Q&A - Nordic DevZone - Nordic DevZone