Evening:
For quite some time I've searched for the correct procedure(S) to get LM 18.3X "live" (usb pendrive) to recognize/accept a casper-rw partiton. Here is an example of what I'm trying to do;
https://www.unix.com/usbubuntu.wordpress.com/make-it-persistent/
...only with LM 18. If you understand what must be done in/with LM 18.3 boot/grub/grub.cfg I'd love to hear from you. This endeavor has taken far to long to achieve. The only other difference there MAY be is that I used Multisystem to install the LM 18.3X O.S. to the pendrive(???) Also, if you know of a better/easier way I'd love to hear that as well.
ThanX:
Rick