The whole /m23 directory is compressed to /mdk/bootCD/iso/m23.tb2, if this file allready exists the /m23 system isn't recompressed. To force recompress simply delete /mdk/bootCD/iso/m23.tb2. Before compression you should clean the /m23 directory from test scripts, dhcp config files and database from all entries.
For cleaning the m23 database: Delete all *.MYD files in /m23/db/m23/ and replace them with empty files. (touch tablename.MYD).
root
2018-05-08