As work-around you can use any 32-bit Linux live system (preferably Debian based, e.g. Ubuntu) and download and run http://buildserver.urbackup.org/restore_cd_2.tar.xz (or build this yourself using the source checkout and ./update_restore.sh).
The build ran but kept failing on the ISO creation. this file did not exist
Reading state information… Done
[2016-10-13 01:19:09] lb chroot_install-packages install
P: Begin installing packages (install pass)…
Reading package lists… Done
Building dependency tree
Reading state information… Done
E: Unable to locate package gnu-fdisk
P: Begin unmounting filesystems…
P: Saving caches…
Reading package lists… Done
Building dependency tree
Reading state information… Done
cp: cannot stat ‘binary.hybrid.iso’: No such file or directory
root@BootPC:~/Downloads/urbackup_cd_build# /root/Downloads/urbackup_cd_build
It did not boot when I put it on a USB stick. The Linux did not want to mount the FAT32 file system. Could have been the specific formatting of my USB stick or a more general problem in Linux 4.7.x.