Game and music running, but no display

[Robin24-5]

Hi, so I tried the project with your ft81x-driver pcb, the same display and your code and made a custom pcb for wiring and the audio. My problem is, that the game is running with sound (I can also hear feedback when I press the buttons), but I can't see anything on the display. Communication with the FT812-Chip seems fine, it is responsive. The all pixels on command directly to the display-controller is also working. I've also reassembled the ft81x-pcb multiple times.
It seems to be a problem in the connection between the ft812 and the display controller.
Has anyone had this problem?