tinygo/targets/arduino-mega2560.json

{
    "inherits": ["atmega2560"],
    "build-tags": ["arduino_mega2560"],
    "ldflags": [
        "-Wl,--defsym=_bootloader_size=8192"
    ],
    "flash-command":"avrdude -c wiring -b 115200 -p atmega2560 -P {port} -U flash:w:{hex} -v -D"
}