https://devzone.nordicsemi.com/f/nordic-q-a/75503/nrf52820-devices-problemok I am using nrf52820 and sdk nRF5_SDK_17.0.2_d674dde when i was using ble_app_uart\pca10100e\s112 Its work correctly and the dfu pca10100e_s112_ble also works correctly but somehow after the application with same hex file of ble_app_uarten-USTelligent Community 13Tue, 25 May 2021 08:21:47 GMThttps://devzone.nordicsemi.com/thread/311347?ContentTypeID=1Tue, 25 May 2021 08:21:47 GMT137ad170-7792-4731-bb38-c0d22fbe4515:1ead6f85-800a-4508-948a-2666355e9b49yu1998<p><span style="font-family:&#39;Times New Roman&#39;, serif;"><span lang="en-US">#ifndef NRF_BL_DFU_ENTER_METHOD_BUTTON</span></span></p> <p><span style="font-family:&#39;Times New Roman&#39;, serif;"><span lang="en-US">//#define NRF_BL_DFU_ENTER_METHOD_BUTTON 1</span></span></p> <p><span style="font-family:&#39;Times New Roman&#39;, serif;"><span lang="en-US">#define NRF_BL_DFU_ENTER_METHOD_BUTTON 0</span></span></p> <p><span style="font-family:&#39;Times New Roman&#39;, serif;"><span lang="en-US">just change this it might work</span></span></p><div style="clear:both;"></div>