https://devzone.nordicsemi.com/f/nordic-q-a/32762/call-to-vportstartfirsttask-fails-in-freertos-when-the-mbr-used-without-the-soft-deviceHi All, I am developing an application on nRF52840 Preview DK which does not need the Soft device. But it needs the MBR to run a bootloader for Firmware update purpose. I&#39;ve taken the MBR from Thread SDK as suggested in: https://devzone.nordicsemien-USTelligent Community 13Tue, 03 Apr 2018 10:44:02 GMThttps://devzone.nordicsemi.com/thread/126629?ContentTypeID=1Tue, 03 Apr 2018 10:44:02 GMT137ad170-7792-4731-bb38-c0d22fbe4515:ed0a429e-6928-4e63-8f4a-7bf4e9d5a676Susheel Nuguru<p>Impressive, you fixed the problem without knowing. So you have done your testing.</p> <p>MBR itself uses some RAM (softdevice used or not (enabled or not)) and it is 8 bytes. You can find more information about it <a href="http://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.s140.sds%2Fdita%2Fsoftdevices%2Fs130%2Fmem_usage%2Fmem_resource_reqs.html">here</a>. This page says that it is softdevice requirements, since they did not account for extracting MBR separately from softdevice.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/126104?ContentTypeID=1Tue, 27 Mar 2018 11:58:12 GMT137ad170-7792-4731-bb38-c0d22fbe4515:e1dd4457-a6a7-471d-9102-38e9f14e02bdRaiyan<p><strong>Update:</strong></p> <p>I have changed line 9 of the linker file with the following line:</p> <p><pre class="ui-code" data-mode="text">RAM (rwx) : ORIGIN = 0x20000010, LENGTH = 0x3FFF0</pre></p> <p>This change made the problem disappear. But I don&#39;t know the reason behind it.</p> <p>I cannot&nbsp;explain how leaving first 0x10 byte in RAM fixes the issue?</p><div style="clear:both;"></div>