https://devzone.nordicsemi.com/f/nordic-q-a/38848/nrf52832-secure-bootloaderHi, I&#39;m working on a custom application using two microcontrollers a pic32 and a nrf52832, I require the pic32 using an external flash memory to read the binary file stored and communicate to the nordic device to flash the firmware, according to theen-USTelligent Community 13Tue, 25 Sep 2018 13:15:46 GMThttps://devzone.nordicsemi.com/thread/150275?ContentTypeID=1Tue, 25 Sep 2018 13:15:46 GMT137ad170-7792-4731-bb38-c0d22fbe4515:0e54c6c2-8fe3-4b69-8e2b-b3700bd543b9Einar Thorsrud<p>Hi,</p> <p>1) The .dat file contain (data for) the <a href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sdk5.v15.2.0/lib_bootloader_dfu_validation.html?cp=4_0_0_3_5_1_1_0#lib_bootloader_dfu_init">init packet</a>, which is needed by the bootloader. There is no way to skip this unless you significantly modify the bootloader (remove signature validation, version checking etc.).</p> <p>2) You are right that there is no SPI transport layer for the bootloader. However, it is designed with multiple transport layers in mind, so it should not be that much work to add a SPI transport layer if needed.</p> <p>3) There is no DFU controller implementation in C. I will create an internal feature request ticket though, as this is a quite common request. Currently we only have a python implementation (<a href="https://github.com/NordicSemiconductor/pc-nrfutil">nrfutil</a>) and <a href="https://github.com/search?q=org%3ANordicSemiconductor+dfu&amp;unscoped_q=dfu">JavaScript implementation as well as libraries for iOS and Android</a>.</p> <p>4) The <a href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sdk5.v15.2.0/lib_dfu_transport.html?cp=4_0_0_3_5_2">DFU protocol</a> is documented on Infocenter as part of the SDK documentation.</p><div style="clear:both;"></div>