https://devzone.nordicsemi.com/f/nordic-q-a/14067/stuck-on-bootloader-when-using-seggerI&#39;m using: nRF51422 SDK 7.1.0 Softdevice S310 2.0.1 nrfjprog.exe v 8.3.0 JLinkARM.dll v 5.10m If I use the Segger with nrfjprog.exe to upload the softdevice, bootloader, and application to the nrf51, it gets stuck on the bootloader, anden-USTelligent Community 13Wed, 25 May 2016 19:29:36 GMThttps://devzone.nordicsemi.com/thread/53788?ContentTypeID=1Wed, 25 May 2016 19:29:36 GMT137ad170-7792-4731-bb38-c0d22fbe4515:26a2cc9c-fc6c-429f-b6d8-38ea9772d610UncleGravity<p>Yes! That was it. I ended up just having to flash the &quot;app_valid_setting_apply.hex&quot; file, found in <a href="https://devzone.nordicsemi.com/question/22056/combining-sd-dfu-and-application-hex-and-programming/?answer=22246#post-id-22246">this post</a>. Thanks so much.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/53787?ContentTypeID=1Wed, 25 May 2016 00:15:13 GMT137ad170-7792-4731-bb38-c0d22fbe4515:7dcc1786-b100-4396-907d-030f3a821509RK<p>Have you read section E of the <a href="https://devzone.nordicsemi.com/blogs/685/common-faq-on-dfu/">Bootloader FAQ</a> and used any of those methods to write 0x01 to the &#39;valid app&#39; address? If not, the bootloader doesn&#39;t know there&#39;s a valid app and will come up in bootloader mode.</p><div style="clear:both;"></div>