v1.4.0

Fixed

• The boot screen was gone before it could be read. The device comes up
  faster than the eye, so LVGL began repainting over the logo within a fraction
  of a second — which looks exactly like an image that does not fit the screen.
  It is now held for one second, and the second is not wasted: the deadline is
  set where the image is drawn and only waited out at the end of startup, so
  LVGL, the language table, the storage read and the reader handshake all happen
  inside it. A board slower than a second to boot waits for nothing.

Added

• ?preview=splash draws the boot screen on demand, so it can be checked from a
  desk. It cannot otherwise be captured: it is shown before the web server
  exists, which is the whole point of drawing it that early.