Set up a NFS server - cesetxeberria/pxeserver GitHub Wiki
Download debian netinst iso, burn it to a cd or a usb and install. Just the minimal install will suffice.
As root user install nfs-kernel-server package.
apt-get install nfs-kernel-server
Modify the /etc/exports file adding a line. You can also edit it with nano.
echo "/home/tftp *(ro,async,no_subtree_check)" >> /etc/exports
Now every other machine in our LAN can read our tft-root folder via NFS. Keep in mind that "/home/tftp" folder must exist. You can add as many folders as you want.
Update servers configuration
exportfs -a