nrf52832 secure bootloader

[Francisco Betancourt]

Hi,

I'm working on a custom application using two microcontrollers a pic32 and a nrf52832, I require the pic32 using an external flash memory to read the binary file stored and communicate to the nordic device to flash the firmware, according to the nordic examples I should use the nrfutil to generate a distribution package and then use the nrfutil with the package generated to load the firmware, this package contains two basic units if I were talking on the case of loading an app firmware, a dat (manifest or dfu settings) file and the binary image of the application to be loaded. The only way the pic32 and the nordic device can communicate is using the SPI interface.

1) Is there a way to simplify this so I don't need the *.dat file and only use the firmware binary image to flash the device? This should work for the sofdevice, bootloader and application images too.

2) I see that the bootloader application has only transports defined for BLE and UART but I don't see any SPI transport, is it difficult to create a new transport based on the UART transport?

3) Is there a c code application available that I can use to port the pc-nrfutil part to load the firmware "send image" to be ported into the pic32 mcu?

4) Where I can find more documentation on the bootloader communication protocol used to flash an application, softdevice and bootloader.

Regards,

Francisco Betancourt

[Einar Thorsrud]

Hi,

1) The .dat file contain (data for) the init packet, which is needed by the bootloader. There is no way to skip this unless you significantly modify the bootloader (remove signature validation, version checking etc.).

2) You are right that there is no SPI transport layer for the bootloader. However, it is designed with multiple transport layers in mind, so it should not be that much work to add a SPI transport layer if needed.

3) There is no DFU controller implementation in C. I will create an internal feature request ticket though, as this is a quite common request. Currently we only have a python implementation (nrfutil) and JavaScript implementation as well as libraries for iOS and Android.

4) The DFU protocol is documented on Infocenter as part of the SDK documentation.