https://devzone.nordicsemi.com/f/nordic-q-a/3074/dfu-error-with-iosDear Sir We got the problem on DFU upload firmware, it always failed in second DFU . We must unpair the device at iOS setting panel. Before next DFU. Here is the log data on iOS and sniffer. (dfu_log.txt) : iOS log data (dfu_error.pcapng) : DFUen-USTelligent Community 13Tue, 14 Nov 2017 10:43:53 GMT