https://devzone.nordicsemi.com/f/nordic-q-a/62174/usb-dfu-trigger-library-problemSDK: 15.3.0 BOARD: custom nRF52840 pre-product Hi, I want to implement usb dfu trigger library. but, faced with a problem. My project are started from usb cli example. I have succeed to display DFU Trigger and CDC ACM in device manageren-USTelligent Community 13Sun, 07 Jun 2020 06:07:31 GMThttps://devzone.nordicsemi.com/thread/253650?ContentTypeID=1Sun, 07 Jun 2020 06:07:31 GMT137ad170-7792-4731-bb38-c0d22fbe4515:66d26349-b06b-41a6-b417-1c524c9269f0_maibi<p>with a little curiosity, I can&#39;t understand why it works. <br />Is there anyone who tell me about this story?</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/253470?ContentTypeID=1Fri, 05 Jun 2020 09:37:26 GMT137ad170-7792-4731-bb38-c0d22fbe4515:baad0868-979b-4240-ae96-eeac02ef1895_maibi<p>I solve this problem.</p> <p><pre class="ui-code" data-mode="text">ret_code_t ret; app_usbd_class_inst_t const * class_cdc_acm = app_usbd_cdc_acm_class_inst_get(&amp;nrf_cli_cdc_acm); ret = app_usbd_class_append(class_cdc_acm); APP_ERROR_CHECK(ret);</pre></p> <p>this code must be after&nbsp;</p> <p><pre class="ui-code" data-mode="text">nrf_dfu_trigger_usb_init();</pre></p> <p>not be before.</p><div style="clear:both;"></div>