Custom DFU bootloader

[mosgaard2000]

Hi,

I have a custom board with the nRF52840.

Is it possible to customize the DFU to be able to update the firmware through other interfaces than BLE or USB/UART?

I have a SD-card connected and would like to check for a flash image on the card and then update the firmware if there is an image.

Would that be possible?

[bjorn-spockeli]

Hi Morten,

the Secure Bootloader in our nRF5 SDK is designed to be transport agnostic. so it should be able to create a custom transport layer, e.g. SPI, that interfaces with the bootloader. 

I would recommend taking a look at the UART transport layer implementation in the nRF5_SDK_15.3.0_59ac345\examples\dfu\secure_bootloader\pca10056_uart example. Specifically, nrf_dfu_serial_uart.c and nrf_dfu_serial.c in the nRF5_SDK_15.3.0_59ac345\components\libraries\bootloader\serial_dfu folder.

They show how the DFU_TRANSPORT_REGISTER macro to register the init and close functions used further up in the bootloader

DFU_TRANSPORT_REGISTER(nrf_dfu_transport_t const uart_dfu_transport) =
{
    .init_func  = uart_dfu_transport_init,
    .close_func = uart_dfu_transport_close,
};

Best regards

Bjørn