“We’ve tried to make it as easy as possible for you to load your code onto your new Raspberry Pi Pico: press and hold the BOOTSEL button, plug your Pico into your computer, and it’ll mount as a mass storage volume. Then just drag and drop a UF2 file onto the board.
However, not everybody is keen to keep unplugging their micro USB cable every time they want to upload a UF2 onto the board. Don’t worry — there’s more than one way around that problem.
Firstly, if you’re developing in MicroPython there isn’t any real need to unplug and replug Pico to write code. The only time you’ll need to do it is the initial upload of the MicroPython firmware, which comes as a UF2. From there on in, you’re talking to the board via the REPL and a serial connection, either in Thonny or some other editor.
However, if you’re developing using our C SDK, then to upload new code to your Pico you have to upload a new UF2. This means you’ll need to unplug and replug the board to put Pico into BOOTSEL mode each time you make a change in your code and want to test it.”