@janotech
which specified device are you using? From your description, you might be using a Core2—its built-in battery won't work with modules. If you're using a CoreS3, UiFlow2 can already turn it into a USB device:
a5da4e48-41a9-4387-ad25-7e25a70cc1ba-image.png
One last question: I'm not sure what you mean by "not even allow the display to work." Have you tried reflashing the firmware?