https://devzone.nordicsemi.com/f/nordic-q-a/67025/recovering-nrf52840-pdk-interface-mcuHi, when powering up the nRF52840 PDK its interface MCU LED is blinking fast and the board is not recognized. I&#39;ve tried to update its firmware by putting the board in bootloader mode and loading this firmware, but nothing is changing. The same processen-USTelligent Community 13Tue, 13 Oct 2020 11:34:12 GMThttps://devzone.nordicsemi.com/thread/274590?ContentTypeID=1Tue, 13 Oct 2020 11:34:12 GMT137ad170-7792-4731-bb38-c0d22fbe4515:73b53a29-c514-42a9-8346-73f83b6adb22Sigurd<p>Hi,</p> <p>Please go through this list:</p> <p><a href="https://devzone.nordicsemi.com/f/nordic-q-a/24592/my-nrf52-nrf51-dk-kit-doesn-t-work">https://devzone.nordicsemi.com/f/nordic-q-a/24592/my-nrf52-nrf51-dk-kit-doesn-t-work</a></p> <p>If you are still not able to get the kit to work after that, you should then buy a new nRF52840 DK. The&nbsp;<span>nRF52840 Preview DK is now deprecated and not recommended for development, </span><span>as the&nbsp;preview kits contains early engineering samples from before the chip was qualified. The&nbsp;engineering samples are not supported in latest SDK versions either. See <a href="https://infocenter.nordicsemi.com/topic/comp_matrix_nrf52840/COMP/nrf52840/nRF52840_ic_rev_sdk_sd_comp_matrix.html">this matrix</a>.</span></p><div style="clear:both;"></div>