By making substantial use of KNOPPIX-DATA on a reiserfs formatted /dev/sda3 I have managed to customise KNOPPIX at boot pretty well as preferred.
However: one final (almost trivial) alteration eludes me.
I would like to tweak the boot init executable file which I think is the one that resides in minirt.gz.
Using a temporary ext2 filesystem as my vehicle for managing this:
1) copy minirt.gz to temp and de-compress minirt.gz using gunzip: this yields a file minirt
2) move to a dofferent subdirectory under temp and extract minirt here with the command cpio -idm < {pathto}/minirt
3) the init file is seen here: edit it - (I'm just tweaking the messages sent to screen at boot) - and save it
4) chmod a+x init and chmod a+w init, as originally found
5) wrap the while thing as a revised minirt to a different subdirectory under temp using find . | cpio -o > {newpathto}/minirt
6) compress the new minirt using gzip --recursive --rsyncable (not sure whether either switch is actiually required)
and finally
7) save the old minirt.gz as minirt.orig.gz in case of failure (see below!)
8 ) copy the new minirt.gz to replace the original.
Then reboot, hoping for success.
But actually get failure at boot with the error message:
"kernel panic - not syncing - unable to mount root fs on unknown-block(0,0)"

I feel I'm almost there at my ideal customised KNOPPIX, and without the hugely complex time-consuming and likely error-prone process of re-mastering.
Has anybody else tried this easier approach and successfully replaced minirt.gz with their own version?

Thank you for any insight or refined practice for 1-8 above .. ..