https://devzone.nordicsemi.com/f/nordic-q-a/103837/problem-flashing-custom-boardWe&#39;ve recently developed our own board based on the nRF52840, using the same schematic as your company&#39;s development boards. We have checked that the power supply on this board is stable, and have even used a stabilised external power supply set to 3Ven-USTelligent Community 13Fri, 15 Sep 2023 18:50:24 GMThttps://devzone.nordicsemi.com/thread/446358?ContentTypeID=1Fri, 15 Sep 2023 18:50:24 GMT137ad170-7792-4731-bb38-c0d22fbe4515:0784fe58-7641-44ef-b119-cb2c893a7e9aAmanda Hsieh<p>Hi,&nbsp;</p> <p>Try to run&nbsp;</p> <p><code>nrfjprog --recover&nbsp;</code></p> <p>on both boards to unlock the board.&nbsp;</p> <p>Let me know if this helps or not.</p> <p>Regards,<br />Amanda H.&nbsp;&nbsp;</p><div style="clear:both;"></div>