They have clearly changed the persistence setup from the last major release (7.6), and I can't see what they are doing - if they even know it themselves. Any mention of "persistence" in init scripts (you won't find it in the main init linked above) was buried deep in some "old" scripts that I couldn't see were called, and the old way of specifying a persistence file doesn't work. Maybe it is compiled in somewhere.

Think the only sensible way out of this is to create a derivative - to honor the Debian live convolution, I think it might be called Simplistix.

If anybody finds out how to tackle the new hurdles, I'd be glad to be informed.

I think 6 parameters should be used: Volume (e.g. /dev/sda1), directory (e.g. live) and name (e.g. filesystem.squashfs) for compressed image and persistent store. It's sensible that image and store are not by default lumped together as in Knoppix, but there is no good reason for forbidding it, like it is in Debian 7.6 live.