Hi,
1) have you patch the dhcp as suggested by z.c ( https://www.zeroshell.org/forum/viewtopic.php?t=2989&highlight=dhcp+howto) ?
I did the same and works 😉 http://www.renatomorano.net/?p=1944
I’ll try to translate my post in English so can be more useful, too
ps.
after patch dhcpd, my advanced options are:
next-server IP_ZEROSHELL_ON_THE_SUBNET;
if exists user-class and option user-class = “iPXE” {
filename = “smartos.ipxe”;
} else {
filename = “undionly.kpxe”;
}