2. Prepare files for PXE-Booting. Generate TFTP -Boot folder structure and files: root@OpenWrt:~# cd /mnt/extstorage root@OpenWrt:~# mkdir tftp tftp/pxelinux.cfg tftp/disks tftp/disks/ubuntu1604-64. Now you have to download syslinux. Download Syslinux Direct-Link to 13-Oct-2013 Syslinux v6.03.