Installation via PXE/TFTP/NFS doesn't work

[mkuron]

I followed the PXE installation guide at http://devwiki.pfsense.org/NetBootSoekrisEmbedded . It works fine for the 1.2-RELEASE, but not for 1.2.1-RC3.
The last lines it shows are:
em0: link state changed to UP
Trying to mount root from nfs:
NFS ROOT: 192.168.200.20:/var/lib/tftpboot/pfsense
I ran Wireshark on it and it seems like it gets stuck after requesting /sbin/init via NFS. Everything up to this point works just fine.

Apparently, this problem also occured in earlier versions (http://forum.pfsense.org/index.php/topic,8797.0.html) and, in this case, may be related to FreeBSD 7.0 (http://www.mydatabasesupport.com/forums/bsd-freebsd-misc/345864-diskless-booting-freebsd-7-0-a.html).