The library is outdated and replaced with implementation over standard Modbus.

esp-Update-over-RS485

1. High level API

class SerialUpdate<HardwareSerial>|<SoftwareSerial> {
	String version;	// Filled with slave current version on slave init (begin())
	SerialUpdate(<HardwareSerial>|<SoftwareSerial>, uint16_t tx);	// Master build constructor
	SerialUpdate(<HardwareSerial>|<SoftwareSerial>, const char* ver = "", uint8_t id = 0);	// Slave constructor
	void begin(uint8_t slaveId = 0);	// Initialize connection to slave
	bool isIdle();	// from RSerial
	bool isReady();	// Actually chcks if version is not ""
	bool sendFile(char* name, File dataSource);		// Send file to slave
	bool sendUpdate(File dataSource);		// Send firmware update to slave
	bool cancel();		// Cancel current send operation
}
Loop functions:
	status_t taskMaster();	// from RSerial
	status_t taskSlave();	// from RSerial

// Update/Transfer commands
// CANCEL_ALL	Cancel current operation
// GET_VERSION	Get/Send version
// BEGIN_UPDATE	Initiate Update
// IMAGE_DATA	Push image data
// END_UPDATE	Finalize update
// FILE_CREATE	Begin file transfer
// FILE_DATA	Push file data
// FILE_CLOSE	Finalize file transfer
// FILE_ERROR	Unrecovarable file/update operation error (Unable to create file, Update or file write error)

2. Packet exchange protocol API

struct packetHeader {
	uint8_t sig[MAGIC_SIG_LENGTH];	// Packet signature
	uint8_t id;						// From/To slave ID
	uint32_t seq;					// Packet sequence #
	uint8_t command;
	uint16_t dataSize;				// Packet data size (Full packet size is sizeof(header) + data size + sizeof(crc32)
};

// Basic commands available
// C_OK	Packet is succefully processed (CRC is Ok no other errors)
// C_ERROR	General packet processing error (structure error or packet oversized)
// C_PING	Ping request/Reply
// C_BADCRC	Packet CRC mismach

union packetFrame {
	packetHeader header;
	uint8_t raw[FRAME_LENGTH];
};

class RSerial<HardwareSerrila>|<SoftwareSerial> {
	RSerial(HardwareSerial|SoftwareSerial serial);
	RSerial(HardwareSerial|SoftwareSerial serial, int16_t max485_tx);
	status_t taskSlave();
	status_t taskMaster();
	void clean();
	status_t send();
	status_t receive();
	virtual status_t processPacketMaster();
	virtual status_t processPacketSlave();
	bool isIdle();
	bool fillFrame(uint8_t com, const char* data, uint8_t slaveId = 0);
	bool fillFrame(uint8_t com, const uint8_t* data, uint16_t len, uint8_t slaveId = 0);
	bool fillFrame(uint8_t com, File data, uint8_t slaveId = 0);
	bool fillFrame(uint8_t com, const R &data, uint8_t slaveId = 0);	// Not tested
};

3. Resources used

Arduino (https://github.com/arduino/Arduino)
Arduino core for the ESP32 (https://github.com/espressif/arduino-esp32)
ESP8266 core for Arduino (https://github.com/esp8266/Arduino)
HTTP server library for ESP8266/ESP32 Arduino cores (https://github.com/emelianov/ESPWebServer)
Run 2017 (https://github.com/emelianov/Run)

Contributions

https://github.com/emelianov/esp-Update-over-RS485

Alexander Emelianov a.m.emelianov@gmail.com