https://devzone.nordicsemi.com/f/nordic-q-a/72990/how-to-disable-nrf-chip-on-nrf52-dk-boardI am using the nRF52-DK board to debug external board. So I am using the P19-Debug out cable. And recently, I notice strange behavior as the on board nRF chip also get programmed with same code as external board. Is there a way to disable on boarden-USTelligent Community 13Fri, 19 Mar 2021 14:02:33 GMThttps://devzone.nordicsemi.com/thread/300968?ContentTypeID=1Fri, 19 Mar 2021 14:02:33 GMT137ad170-7792-4731-bb38-c0d22fbe4515:f2949c6a-f42d-4720-82c4-017e7882ce13Jared<p>Hi,</p> <p>If the debugger doesn&#39;t sense the VDD on the external DUT then it will flash the nRF IC on the DK instead. You could cut SB9, this will prevent the debugger from flashing the nRF and a error message will be returned, but it will not fix the actual problem. You should check the VDD on the DUT.</p> <p>regards</p> <p>Jared&nbsp;</p><div style="clear:both;"></div>