NRF5340 has a 90 ms delay from reset/power-on to first CPU instruction (MCUboot EARLY init)https://devzone.nordicsemi.com/f/nordic-q-a/127533/nrf5340-has-a-90-ms-delay-from-reset-power-on-to-first-cpu-instruction-mcuboot-early-initSetup SDK/OS: nRF Connect SDK v3.1.0 , Zephyr v4.1.99 Board: custom board Summary I am measuring the time from reset (or power-on) to the first user code execution on the nRF5340 application core. Consistently, 90 ms elapses before myen-USTelligent Community 13Mon, 23 Mar 2026 14:06:10 GMTRE: NRF5340 has a 90 ms delay from reset/power-on to first CPU instruction (MCUboot EARLY init)https://devzone.nordicsemi.com/thread/563890?ContentTypeID=1Mon, 23 Mar 2026 14:06:10 GMT137ad170-7792-4731-bb38-c0d22fbe4515:03e678be-6249-428d-9850-1e6f17cec4b4Menon<p>Hello,</p> <p>I don’t think this delay is expected. Could you share your MCUboot configuration? Also, are MCUboot logs or shell enabled? If they are, please try disabling them and see whether the startup time changes.</p> <p>Kind Regards,</p> <p>Abhijith</p><div style="clear:both;"></div>RE: NRF5340 has a 90 ms delay from reset/power-on to first CPU instruction (MCUboot EARLY init)https://devzone.nordicsemi.com/thread/563807?ContentTypeID=1Sat, 21 Mar 2026 08:19:39 GMT137ad170-7792-4731-bb38-c0d22fbe4515:bc393827-5c53-4bcc-8c6c-a6eb34284687Turbo J<p>See Datasheet/PS chapter 4.10.12.1 &quot;Application core startup times&quot;.</p> <p>The code will run after memory initialization (copy flash to data RAM, set bss to zero) but thats a few ms IMHO.</p><div style="clear:both;"></div>