https://devzone.nordicsemi.com/f/nordic-q-a/102473/nrf52833-buttonless-dfu-cannot-enter-to-bootloaderHi there is urgent question , I would like to ask how to enter the bootloader mode to apply the dfu OTA function, I was added buttonless DFU service in my ble peripheral project. then added the BLE secure bootloader as my DFU bootloader. the 1sten-USTelligent Community 13Wed, 02 Aug 2023 11:08:56 GMThttps://devzone.nordicsemi.com/thread/439472?ContentTypeID=1Wed, 02 Aug 2023 11:08:56 GMT137ad170-7792-4731-bb38-c0d22fbe4515:45ea4cbe-83d1-4297-a4a3-fe219a7d83ffHung Bui<p>Hi Kawing,&nbsp;</p> <p>Do you see the same behavior with the buttonless example ?&nbsp;<br />If you don&#39;t then there must be something wrong with the implementation in your application.&nbsp;</p> <p>On the first run after you flash the bootloader it will always enter DFU mode because there is no valid application to start.&nbsp;</p> <p>If you use the debug version of the bootloader you will be able to step into the bootloader mode. Make sure you do a full chip erase if you switch between non-debug and debug version of the bootloader.&nbsp;</p><div style="clear:both;"></div>