I searched the board on the ramlib and I see that its task is to call the libs. So you're right, Piru; as usual sigh... ;-)
Anyway with my limited knowledge I don't know what to do next. I find it strange that it works when I start without startup-sequence. I mean the ROM is the same and it even works if I run Setpatch after that.
I'll try with the SetJoyPort now...