- Adjust `PROG_DEV` to the device your board is connected to. On Linux it's usually `/dev/ttyUSB0`, but it can also be `/dev/ttyACM0` or something else. On Mac, it'll be `/dev/cu.xxx`. On Windows it's some `COMx`.
Linux and Mac users can just `ls /dev` to see what devices they have. Windows users will find this in their Device Manager.
- You may also adjust the baudrate (`PROG_BAUD`). Some boards need `115200`.
**TIP:** You can look what the Arduino IDE is using - it's running avrdude too.