> What does the -s option do?

When using the "-s dir" flag with a directory name, tftpd will
chroot(2) on startup to the given "dir".

The -s flag appeared in NetBSD 0.9a.  I guess you probably wouldn't
have it on Linux.

It seems pretty secure, it allows old Sun3s to ask for files with no
path given.  To deal with machines that ask for "/tftpboot/mystartfile"
do "cd /tftpboot; ln -s . tftpboot"

~Ken