Is the missing memory allocated as a ram-disk in the same way the original Sharp images worked?
what does 'cat /proc/meminfo' show?
I'd expect a small amount of memory to be missing in an OZ image to mount things like /tmp, /var in a tmpfs (though I don't know whether Cacko does this), but certainly not 17Mb straight after boot (I assume that's where you are). If you've actually been doing things, and do have a tmpfs, then (on OZ at least) it's allowed to grow up to half the available memory, so you might want to check this too.
Si