https://devzone.nordicsemi.com/f/nordic-q-a/2446/why-always-enter-into-dfu-mode-after-i-connect-the-power-supplyHi I&#39;m working on the DFU feature according to the &quot;device_firmware_updates&quot; example on PCA1001 board, basically it works, but the question I&#39;m facing is the board always enter into DFU mode after I connect the power supply(USB cable) with the boarden-USTelligent Community 13Wed, 14 May 2014 15:06:39 GMThttps://devzone.nordicsemi.com/thread/9886?ContentTypeID=1Wed, 14 May 2014 15:06:39 GMT137ad170-7792-4731-bb38-c0d22fbe4515:5e63b38d-2f84-461f-8d8c-df915e47886dHung Bui<p>Hi Tao,</p> <p>Have you modified the buttons_init() to match with the configuration PCA10001 ? The device firmware update was made for the DevKit that has external pull up resistor on the pin. I suspect that when you connect the board via USB, there might be a pulse on the pin that forced the DFU bootloader to start. I would suggest to change the BUTTON_PULL from NRF_GPIO_PIN_NOPULL to BUTTON_PULL GPIO_PIN_CNF_PULL_Pullup.</p><div style="clear:both;"></div>