building for diskless support: unknown option mfs

[Guido Van Hoecke]

Hi,
I try to build a kernel that supports dsikless booting (on a  
FreeBSD-RELEASE-6.0). I have copied the GENERIC config file as DISKLESS  
and added following lines (as described in  
/usr/share/examples/diskless/clone_root:

	options MFS
	options BOOTP
	options BOOTP_NFSROOT
	options BOOTP_COMPAT

When I start building the DISKLESS kernel, I get following output:

23:58:56 beastie:/usr/src# make buildkernel KERNCONF=DISKLESS

--------------------------------------------------------------
>>> Kernel build for DISKLESS started on Sun Feb 26 23:59:30 CET 2006
--------------------------------------------------------------
===> DISKLESS
mkdir -p /usr/obj/usr/src/sys

--------------------------------------------------------------
>>> stage 1: configuring the kernel
--------------------------------------------------------------
cd /usr/src/sys/i386/conf;   
PATH=/usr/obj/usr/src/tmp/legacy/usr/sbin:/usr/obj/usr/src/tmp/legacy/usr/bin:/usr/obj/usr/src/tmp/legacy/usr/games:/usr/obj/usr/src/tmp/usr/sbin:/usr/obj/usr/src/tmp/usr/bin:/usr/obj/usr/src/tmp/usr/games:/sbin:/bin:/usr/sbin:/usr/bin   
config  -d /usr/obj/usr/src/sys/DISKLESS  /usr/src/sys/i386/conf/DISKLESS
/usr/src/sys/i386/conf/DISKLESS: unknown option "MFS"
*** Error code 1

Stop in /usr/src.
*** Error code 1

Stop in /usr/src.
23:59:30 beastie:/usr/src#

Did I overlook something? Is this option obsolete or so? It is not  
mentioned in the handbook.

Please advise.

TIA, Guido.