See NodeJsController/Readme.md for usage instructions...

Technical details to write your own controller

All initialization the bootloader does (finding parent / requesting nodeId on first start) uses the same packets as a normal MySensors sketch. There is no need for the controller to distinguish between packets from the bootloader and packets from normal sketch execution. The controller only needs to care about two additional request/response communications. All communication is binary.

FirmwareConfig

Firmware

typedef struct
{
 uint16_t type;
 uint16_t version;
 uint16_t block;
 uint8_t data[FIRMWARE_BLOCK_SIZE];
} FirmwareResponse;