i made a fresh installation today and there it works perfectly.
I can even see the rainbow now at the start.
i could only found pluto-boot-scripts. is that the right one?
i compared the version of the new installationhttps://paste.ubuntu.com/23230006/
with my "old" installation:https://paste.ubuntu.com/23230134/
don`t know whats wrong with my old installation...
now i only have my old problems with my new installation, that i cannot listen to any music or see any video from my hybrid/core.
i think it is again the low nfs-speed.
will investigate that problem now. ( will try to watch something from another location than my media hd in my core )
So thank You very much for You help and Your work!
Q.E.D. It works!
Shall i provide any more information or should i just switch to my new installation?