https://devzone.nordicsemi.com/f/nordic-q-a/70634/nrf52---serial-dfu-with-application-requiring-softdevice-fails-to-boot-application-after-updateHi, I am trying to setup the serial UART DFU process for a custom board. I am able to build and program a combined firmware hex file which includes - Softdevice S140 (6.1.1), secured serial bootloader (pca10056_uart_debug), Application, and a settingsen-USTelligent Community 13Wed, 20 Jan 2021 01:51:30 GMThttps://devzone.nordicsemi.com/thread/290095?ContentTypeID=1Wed, 20 Jan 2021 01:51:30 GMT137ad170-7792-4731-bb38-c0d22fbe4515:43632e4b-293f-43da-8269-ea42e7479c25Jimit<p>yes, that worked. Thanks!</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/290014?ContentTypeID=1Tue, 19 Jan 2021 13:35:12 GMT137ad170-7792-4731-bb38-c0d22fbe4515:1f74e968-6c2b-42cf-8cf3-4c3cc92341e5Amanda Hsieh<p>Hi,&nbsp;</p> <p>Does the SD already exist on the device before you update the application? If no, you should program SD and the&nbsp;<span>secured serial bootloader (pca10056_uart_debug) before you update the application. Refer to the&nbsp;</span><a title="Generating and displaying bootloader settings" href="https://infocenter.nordicsemi.com/topic/ug_nrfutil/UG/nrfutil/nrfutil_settings_generate_display.html?cp=9_5_6">Generating and displaying bootloader settings</a>&nbsp;to generate the setting for the application (remove&nbsp;<strong>--softdevice s140_nrf52_6.1.1_softdevice.hex </strong>), merge the setting with the application image, generate the package with&nbsp;<strong>--sd-req 0xB6 </strong>for&nbsp;Softdevice S140 (6.1.1). If it still fails, please update and post the commands you are using.&nbsp;&nbsp;</p> <p>-Amanda H.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/289898?ContentTypeID=1Tue, 19 Jan 2021 01:59:44 GMT137ad170-7792-4731-bb38-c0d22fbe4515:5607d05e-c7ea-4d3c-912a-7cb645dad7ceJimit<p>I am using NRF52 SDK 15.3.0</p><div style="clear:both;"></div>