update: When I tick the “Aktualisieren der HDMI-Ausgabe”, it still doesn’t work but then comes the login page for the Desktop.
I tried to login with “Kodi” (login:pi pass:raspberry) but it failed. Then I tried to login with “Defaut Xsession” and that works.
I can see Kodi under Menu/sound&video but it won’t start.
(My Monitor is connected via HDMI/DVI adaptor and I can’t test with a pure HDMI connection but never had issues)