The firmware development mode is the default with the IFMCU DISCONN switch (SW6) in the left position.
The primary interface for programming and debugging the nRF9160 DK is the Universal Serial Bus (USB) port (J6). The USB port is connected to an interface MCU which embeds a SEGGER J-Link-OB (On Board) debug probe.
Figure 1. nRF9160 DK firmware development mode
