> Display connected to the microcontroller instead of the Linux SoC is an interesting choice

There's a comment at the bottom about that. Quoting the response:

> From the Linux side, it's a standard framebuffer and keyboard that applications interact with as usual. However, our connection allows the MCU to intercept them and overlay additional content — for example, if the CPU hangs, we can still show a menu on the display and respond to button presses, say for a reboot. This also lets us have a low-power mode with the display still on.

Which sounds reasonable.