Copy in the required syslinux files (tftp cannot follow links outside of it's allowed directories, so you'll need to copy these in)
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cp /usr/share/syslinux/pxelinux.0 .
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cp /usr/share/syslinux/memdisk .
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Download the latest copy of the ubcd iso [http://www.ultimatebootcd.com/download.html from] into the /tftpboot/ubcd directory and create a link to it (my default file looks for ubcd.iso)