DFU Functionality - Serial image bootloader

DFU, the device firmware upgrade in bootloader is used to load new image which is received from host over serial interface and writes into the internal flash or external flash. The host may be python script or pc tool.

There are two possible ways the device bootloader can be put into DFU mode

GPIO trigger DFU Mode
By holding GPIO pin/button and resetting the board helps to enter DFU mode