https://devzone.nordicsemi.com/f/nordic-q-a/2623/bootloader-hangupHi, I don&#39;t have any problems running the bootloader with S110 7.0.0.-3.alpha on the PCA1001 but when using the same code (minus the led and button config of the PCA1001) on my custom board the bootloader always crashes on sd_mbr_command(&amp;com); inen-USTelligent Community 13Tue, 27 May 2014 08:01:27 GMThttps://devzone.nordicsemi.com/thread/10359?ContentTypeID=1Tue, 27 May 2014 08:01:27 GMT137ad170-7792-4731-bb38-c0d22fbe4515:ec1bba66-7135-48d7-8709-65f19b817551Mathias<p>I have found the problem myself, I have forgot to change the cpu source in the bootloader :(</p> <p>I had to change</p> <p>SOFTDEVICE_HANDLER_INIT(NRF_CLOCK_LFCLKSRC_XTAL_20_PPM, true);</p> <p>to</p> <p>SOFTDEVICE_HANDLER_INIT(NRF_CLOCK_LFCLKSRC_RC_250_PPM_4000MS_CALIBRATION, true);</p> <p>and now it works perfectly! ;)</p> <p>Best regards, Mathias</p><div style="clear:both;"></div>