Actually Beastie that did help, thank you. It wasn't exactly the same problem that had occured in your link but I repeated the installation and played around with the cylinder 'settings'. I did manage to get the machine booting again. This seems to me like a bug in the FreeBSD boot manager as, if I don't install it and set up Grub manually instead, Grub just works and can also be replaced via fixmbr - something that didn't work with the FreeBSD BM. Should I file this as a bug report, and if so where?