https://devzone.nordicsemi.com/f/nordic-q-a/82576/failed-to-power-up-dap-successfully-resolved-possible-causesHi all, we recently had a problem with couple of our boards based on Raytac MDBT50Q-1MV2 (nrf52840 + osc. + antenna). We base our app on Zephyr. After programming some boards (cca 5% of the batch) using Segger EDU mini they became unresponsive, anden-USTelligent Community 13Thu, 12 May 2022 15:07:52 GMThttps://devzone.nordicsemi.com/thread/367691?ContentTypeID=1Thu, 12 May 2022 15:07:52 GMT137ad170-7792-4731-bb38-c0d22fbe4515:ee602ca4-6107-486a-aaa6-8d97d8d9e595Matevz B<p>Thank you very much for this hint. It has saved many hours of debugging. The board is no longer brciked!</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/342853?ContentTypeID=1Fri, 10 Dec 2021 08:55:27 GMT137ad170-7792-4731-bb38-c0d22fbe4515:7e0c3166-6256-4427-a797-e1ee9e3ea051Kenneth<p>You should look into whether you may have&nbsp;CONFIG_GPIO_AS_PINRESET in your defines, if it is defined, then in system_nrf52.c it will be used to enable pin reset:<br /><a href="https://infocenter.nordicsemi.com/topic/ps_nrf52840/uicr.html#register.PSELRESET-0-1">https://infocenter.nordicsemi.com/topic/ps_nrf52840/uicr.html#register.PSELRESET-0-1</a>&nbsp;</p> <p>If it&#39;s enabled you can check by:<br /><img src="https://devzone.nordicsemi.com/resized-image/__size/640x480/__key/communityserver-discussions-components-files/4/3603.pastedimage1639126580223v1.png" alt=" " /></p> <p>Unfortunately if your code set this pin output low and/or configure pull-down, then it may be that the the chip is stuck in a infinite pin reset. The only way is to force it high externally in such case. I can&#39;t think of other reasons why it was low (other than electrical problems externally though, e.g. soldering residue).</p><div style="clear:both;"></div>