https://devzone.nordicsemi.com/f/nordic-q-a/64826/issue-while-debuggingHello, I&#39;m using Segger ES 4.52 and I&#39;m having some issues while doing step by step debugging. It tells me that some symbols are not defined, even if they actually are (see the picture attached, on the top right). Any idea of what the problem mayen-USTelligent Community 13Fri, 14 Aug 2020 21:21:11 GMThttps://devzone.nordicsemi.com/thread/264677?ContentTypeID=1Fri, 14 Aug 2020 21:21:11 GMT137ad170-7792-4731-bb38-c0d22fbe4515:23de2c2c-baaa-4b10-86f0-4012e7a5b617Simon<p>Try to follow the steps in <a href="https://devzone.nordicsemi.com/nordic/nrf-connect-sdk-guides/b/getting-started/posts/nrf-connect-sdk-tutorial---part-3-temporary#h131sk0f71xdy1hliuda1vq9p8n11weqgr">NCS tutorial part 3&rarr;Debugging</a>. To enable optimizations, as&nbsp;<a class="internal-link view-user-profile" href="https://devzone.nordicsemi.com/members/awneil">awneil</a>&nbsp;mentioned, set&nbsp;CONFIG_DEBUG_OPTIMIZATIONS=y.</p> <p>Best regards,</p> <p>Simon</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/264660?ContentTypeID=1Fri, 14 Aug 2020 15:31:57 GMT137ad170-7792-4731-bb38-c0d22fbe4515:9262f9e0-6c4c-4c0d-9e48-ef0498aa7955awneil[quote userid="92623" url="~/f/nordic-q-a/64826/issue-while-debugging"]Any idea of what the problem may be[/quote] <p>Optimisation (or Optimization).</p> <p>Although this article focuses on GCC, this is a general thing with compiled languages: not just &#39;C&#39;, and not specific to Nordic or SES or GCC:</p> <p><a href="https://www.avrfreaks.net/forum/tutcoptimization-and-importance-volatile-gcc">https://www.avrfreaks.net/forum/tutcoptimization-and-importance-volatile-gcc</a></p><div style="clear:both;"></div>