Did you use chroot? Maybe that is also because debian clears /tmp on boot? To communicate with dsme you need to leave /tmp/dsmesock in place. /tmp and /mnt/initfs/tmp is same place (mounted via -o bind in /linuxrc) so even chrooted dsmetest does not work if /tmp is cleared. Maybe you can unmount it before letting debian to clear it. You should perhaps remount it anyway, it is tmpfs limited to 512kb which may be too small for debian.