https://devzone.nordicsemi.com/f/nordic-q-a/53051/sdk-9-0-ble-serial-dual-bootloaderWe have a custom board with nrf51822 chipset, and we need to implement the firmware update process, which can support both over-the-air and uart type firmware update. 1、Just an update - I was able to test the UART DFU and it works,Route:nRF51_SDK_9en-USTelligent Community 13Tue, 14 Nov 2017 10:43:53 GMT