Hi, I already have device that plays audio from sd card. New feature is needed that user can send MP3 file to device from mobile phone that will be stored in sd card and then played on request. So I am not talking about streaming. I was wondering if there exists nordic example on reliable file sending, that would include ble service for nrf and code for mobile? I am thinking of reusing DFU code. It should provide me all features I need like restarting interrupted sending and missed/corrupted bytes detection base on crc. I am just wondering if DFU doesnt have too much overhead and maybe there is faster/better way to send big file?