https://devzone.nordicsemi.com/f/nordic-q-a/11826/bootloader-can-t-switch-to-application-using-mergehex-toolHi, In my project I need to program softdevice+bootloader+application at a time, for these previously I used mergehex tool to merge Softdevice, Bootloader,application and app_valid_setting_appy.hex and created single hex file and programmed by using nrfjprogen-USTelligent Community 13Thu, 11 Feb 2016 12:24:08 GMThttps://devzone.nordicsemi.com/thread/44728?ContentTypeID=1Thu, 11 Feb 2016 12:24:08 GMT137ad170-7792-4731-bb38-c0d22fbe4515:d50af510-984f-40b6-9380-170bcb7aa64bVidar Berg<p>Difference between the normal bootloader and the one with signing is that the sec module is located at the same flash page as bootloader settings. So it is possible that the app_valid _setting_apply.hex has to be modified to work with the signing bootlaoder.</p> <p>With that being said, I think it should be easier to just set the app flag manually with nrfjprog or set set the flag in your bootloader code. See question &#39;E&#39; in this <a href="https://devzone.nordicsemi.com/blogs/685/common-faq-on-dfu/">FAQ</a> for instructions on how to do this.</p><div style="clear:both;"></div>