I'm owning a CarPlay head unit from Volkswagen called RCD330 plus. It is possible to upgrade/downgrade to any available firmwares. For example here are two firmware versions: http://rcd330plus.com/rcd/variantconflict_Eror.rar
The firmware file itself is a *.tar file and can be extracted. I found a linux file structure (var, etc, opt, ... folders).
The head unit supports only a few languages like Chinese, Mexican, US English, ... and I want to add support for German language.
What I tried already
Where can I get information/knowledge to add an additional language. Maybe also with adding german language flag in the setup menu of the radio? Or is this just impossible?
Is this hmi file a compiled file or is it kind of some archiv which can be somehow extracted?