Seems to have been a hardware problem, sorry for beeing rude. The machine needed a restart and looking at the BIOS the hard-drive data seemed quite odd, surely enough an autodetect failed... After a bit fidling with the cables not only did could BIOS see the HDD again and the new kernel booted without a problem. Not sure what exactly was wrong, but as long as it works...
Seems to have been a hardware problem, sorry for beeing rude. The machine needed a restart and looking at the BIOS the hard-drive data seemed quite odd, surely enough an autodetect failed... After a bit fidling with the cables not only did could BIOS see the HDD again and the new kernel booted without a problem. Not sure what exactly was wrong, but as long as it works...