How does DFU mode transmit data over Bluetooth

[wasdwasd0105]

Hello,

We want to develop a program that can send and update the firmware using Linux. And I found there is only a DFU demo app for android and ios. I want to know how the updater extract and send the firmware to the NRF devices. 

Thank you

[esisk]

Once you figure out how to transfer the update firmware file to the chip, if you are using NCS instead of nRF5 SDK (which is a good idea) I'd suggest taking a look at the dfu_target library DFU target — nRF Connect SDK 1.6.99 documentation (nordicsemi.com), basing the flow of calling the library outlined by fota_download.c found in <sdk-root>\nrf\subsys\net\lib\fota_download\src\fota_download.c, and using MCUBoot as your bootloader Adding a bootloader chain — nRF Connect SDK 1.6.99 documentation (nordicsemi.com) As for transferring the file via Bluetooth, I do not know much about that but it is mainly independent of the DFU process