Hi Janneke,

>[0]: A difficulty here is that the Pinebook Pro currently does not want to show
>a U-Boot prompt, command line or debug output. If you consider to buy one, you
>may want to also order a serial cable that might help debugging the boot
>sequence.

Could you file a bug report upstream?

It should be possible (and much less weird) for the vendor to just enable the
TFT display in u-boot and display stuff there.

(linux-sunxi, the dev group for another ARM SoC vendor, does it just fine in
mainline u-boot--so it is possible and can maybe be copied)