Quick'n'dirty workaround: Edit /var/lib/dpkg/info/uswsusp.config to output its message somewhere else. The message is triggered by missing sys in chroot, so a mount --bind could help better. (I didn't try) /proc is missing too. /dev/sdterr is symlinked via /proc/fd... to /dev/pts/... . But bind-mounting /proc to $livesystembuildingdirectory/chroot/proc did not help and causes the same error-message as in my initial report.