This changes appupdate.py to get the filesystem size at runtime. This will
allow the code to be shared with LEGO_HUB_NO7 which has a similar flash
chip with a different size.
Signed-off-by: David Lechner <david@pybricks.com>
This changes all uses of pins to use the alias names of the pins. This
makes the code easier to understand and will also allow sharing more code
with LEGO_HUB_NO7.
Signed-off-by: David Lechner <david@pybricks.com>