# mkdir /tmp/rip1 /tmp/rip2
# mount -o loop RIPLinuX-13.7.iso /tmp/rip1
# cp -a /tmp/rip1/* /tmp/rip2
# umount /tmp/rip1 ; rmdir /tmp/rip1
# mkdir /tmp/rip2/boot/1
# cd /tmp/rip2/boot/1
/tmp/rip2/boot/1# gzip -dc ../rootfs.cgz | cpio -iumdv
Make the changes and remove the old system.
/tmp/rip2/boot/1# rm ../rootfs.cgz
Then cpio/gzip the new system.
/tmp/rip2/boot/1# find . | bin/cpio -v -o -H newc | gzip -9 >../rootfs.cgz
                             ^^^
                     "Use 'bin/cpio' from rootfs, because the version
                      on your system may cause a problem!"