Currently, there is no way to load persistent settings if Knoppix is booted from a read-only medium. I suggest a change to the init script in the minirt, so that it is possible e.g. to boot from a CD and enter a boot parameter to load the KNOPPIX-DATA overlay file from a file somewhere else.
Code:
knoppix home=/dev/sdb1/path/to/file/loadme
should load the file loadme.img or loadme.aes from the stated device and path.

diff between original init and the new version:
Code:
848a849,871
> preparehome(){
> # mount device and set the correct mounted path in $home
>   DEVICE=`echo $home | awk -F/ '{print "/"$2"/"$3}'`
>   HOMEFILE="${home#$DEVICE/}"
>   #check if the device is already mounted
>   MOUNTED=`mount | grep ^$DEVICE | awk '{print $3}'`
>   if [ -n "$MOUNTED" ]
>   then
>     if [ -r "$MOUNTED"/${HOMEFILE}.* ]
>     then
>       home="$MOUNTED"/${HOMEFILE}
>     fi
>   else
>     # make mount point
>     [ -d /mnt-home ] || mkdir -m 755 /mnt-home
>     trymount "$DEVICE" /mnt-home >/dev/null 2>&1
>     if [ -r /mnt-home/${HOMEFILE}.* ]
>     then
>       home=/mnt-home/${HOMEFILE}
>     fi
>   fi # if mounted
> } # preparehome
> 
850a874,875
>  # if home is in parameters and starts with /dev/ mount the device and find the file
>  [ -n "$home" ] && [ `echo $home | awk -F/ '{print $2}'` = "dev" ] && preparehome
What's the point ? To be able to use an unmodified verifiable ISO and still load settings. Some computers cannot boot from USB, and maybe one isn't allowed to copy Knoppix to the hard disk.