https://devzone.nordicsemi.com/f/nordic-q-a/14621/how-to-upgrade-firmware-throught-external-spi-flashhi, when i run the application , i used the external spi flash to download the firmware from my company&#39;s server, then make a upgrade flag to the spi flash and reset the chip. how can i write a basic bootloader to move the firmware to the applicationen-USTelligent Community 13Tue, 21 Jun 2016 11:33:05 GMThttps://devzone.nordicsemi.com/thread/55795?ContentTypeID=1Tue, 21 Jun 2016 11:33:05 GMT137ad170-7792-4731-bb38-c0d22fbe4515:dcf2e44a-0b0b-4d28-b9b8-53015f47ff10Hung Bui<p>Hi Dasu,</p> <p>We don&#39;t have that type of bootloader yet. You may have to write your own code for the bootloader to copy the image from the external SPI flash to the internal one.</p> <p>Do you have softdevice on your chip ? If you do, you can follow what we have with the current bootloader on how to forward the vector table and branch the program counter to start application. If you don&#39;t have a softdevice, you can have a look at our example <a href="https://devzone.nordicsemi.com/question/33621/how-to-make-the-nrf51822-flash-jump-successful-without-softdevice/?answer=33678#post-id-33678">here</a>.</p><div style="clear:both;"></div>