https://devzone.nordicsemi.com/f/nordic-q-a/21956/firmware-not-started-when-bootloader-existsI&#39;ve compiled the secured DFU bootloader (from SDK 12.2) and loaded it on my board. But whenever I run my firmware, it won&#39;t start (none of the expected interaction happens), moreover, if I put a breakpoint at the beginning of my main(), it won&#39;t breaken-USTelligent Community 13Fri, 12 May 2017 14:08:25 GMThttps://devzone.nordicsemi.com/thread/86165?ContentTypeID=1Fri, 12 May 2017 14:08:25 GMT137ad170-7792-4731-bb38-c0d22fbe4515:4edcc2f6-11e1-4eec-90a5-b1d8f75185b3bjorn-spockeli<p>Hi Jonathan,</p> <p>this is the expected behavior if you flash Bootloader, Application and SoftDevice to your device using a programmer. The bootloader will check the bootloader settings flash page to see if the valid application flag is set, which is set to false by default. You need to generate a bootloader settings hex using nrfutil and merge this with the bootloader hex in order to set the valid app flag. This is described in Appendix 1 of <a href="https://devzone.nordicsemi.com/blogs/1085/getting-started-with-nordics-secure-dfu-bootloader/">this</a> blog post.</p> <p>Best regards</p> <p>Bjørn</p><div style="clear:both;"></div>