e
   device into its "Boot Loader" mode, where it accepts new firmware
   installs.
</p>
<p>
   The Pico's Boot Loader mode is built directly into the Pico's CPU,
   in physically un-erasable ROM.  It's ready to go when you take a
   new Pico out of the box, and it'll still be there no matter how many
   different firmware programs you install.
</p>
<p>
   To activate Boot Loader mode, you have to do a little deft button-pressing
   and cord-plugging:
</p>
<ul>
   <li>Unplug the USB cable from the Pico (and