https://devzone.nordicsemi.com/f/nordic-q-a/32603/dfu-over-uartI have custom board with nrf52832. I use latest nrf5 sdk 14. Problem is that when I am connected with SWD and RTT then everything works perfectly. But when I disconnect SWD then pc-nrfutil starts to response. I use bootloader_secure_serial example. en-USTelligent Community 13Thu, 22 Mar 2018 12:14:10 GMThttps://devzone.nordicsemi.com/thread/125519?ContentTypeID=1Thu, 22 Mar 2018 12:14:10 GMT137ad170-7792-4731-bb38-c0d22fbe4515:d4078b8e-08a0-461d-94ee-e8f92ed1d2d9Maidu<p>FIxed it. Problem was in clock. Did not have second crystal on that board and needed to change&nbsp;</p> <pre><span>CLOCK_CONFIG_LF_SRC</span> to 0</pre><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/125366?ContentTypeID=1Wed, 21 Mar 2018 14:00:33 GMT137ad170-7792-4731-bb38-c0d22fbe4515:76d1a726-3742-4515-9b9a-0bbf30a41816Maidu<p>I did one test and forwarded UART input to output in DFU code and UART data transfer was ok.</p><div style="clear:both;"></div>