Someone broke diskless booting

Some time in the past week or so someone committed a change to the
kernel that broke diskless booting:

Trying to mount root from nfs:
fxp0: link state changed to UP
NFS ROOT: 69.147.83.43:/a/nfs/7.dir1
Interface fxp0 IP-Address 69.147.83.96 Broadcast 69.147.83.127
mdmfs: mdconfig (attach) exited with error code 1
cp: /etc/gss/mech: Read-only file system
cp: /etc/gss/qop: Read-only file system
cp: utimes: /etc/gss: Read-only file system
cp: /etc/ppp/ppp.conf: Read-only file system
...
nfs server 69.147.83.43:/a/nfs/7.dir1: not responding
nfs server 69.147.83.43:/a/nfs/7.dir1: not responding
nfs server 69.147.83.43:/a/nfs/7.dir1: not responding

Kris