https://devzone.nordicsemi.com/f/nordic-q-a/74774/advices-to-implement-custom-dfuOn a custom board based on nrf52840. We want to implement OTA DFU with radio (not necessarily BLE, e.g Serial 4G Modem) We already checked the Serial DFU example and made it work on our board without SoftDevice, but we want to have the following specificationsen-USTelligent Community 13Thu, 06 May 2021 12:04:54 GMThttps://devzone.nordicsemi.com/thread/308545?ContentTypeID=1Thu, 06 May 2021 12:04:54 GMT137ad170-7792-4731-bb38-c0d22fbe4515:13b492fb-537f-49de-aa43-10affaa04853Vidar Berg<p>Hello,</p> <p>Our SDK bootloader supports app handled FW updates of application images as discussed in this post: <a href="https://devzone.nordicsemi.com/f/nordic-q-a/46994/background-dfu-application-source-code">https://devzone.nordicsemi.com/f/nordic-q-a/46994/background-dfu-application-source-code</a>. However, it does not support the AB-model you described. I.e. you can&#39;t revert an update after it has been verified and activated by the bootloader.</p> <p>Have you also considered the open source MCUboot (<a href="https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/mcuboot/wrapper.html">link</a>) implementation we are using in our new nRF connect SDK? Memfault has a blog post on how you can port this bootloader that may be of interest: <a href="https://interrupt.memfault.com/blog/mcuboot-overview">https://interrupt.memfault.com/blog/mcuboot-overview</a></p><div style="clear:both;"></div>