apt install ipxe
cd /your-tftp-root
mkdir -p {bios,uefi}
ln -s /usr/lib/ipxe/undionly.kpxe ./bios/
ln -s /boot/ipxe.efi ./uefi/
FQDN=DNS-name-of-your-server-here
IP_OF_FQDN=`dig $FQDN +short`
cat <<EOF>x2go-tce-ipxe
#!ipxe
dhcp
kernel http://$FQDN/x2go-tce-vmlinuz EVERYTHING-FROM-THE-LINE-STARTING-WITH-APPEND-IN-THE-X2GO-TCE-SAMPLE-FILE-ABOVE
initrd http://$FQDN/x2go-tce-initrd.img
boot
EOF