I'm trying to create a fresh ISO image for use on a USB stick. I've partitioned my USB stick into 2 partitions, one
vfat and one
vfat partition has the ISO and
GRUB2 installed to it, such that
GRUB2 boots the ISO.
ext4 partition has the volume label
casper-rw and is used as the persistent data store for the Live USB. I've modified the
grub.cfg such that I get two options at boot, one to boot the ISO in persistent mode and one to boot normally.
However, when booting in "normal" mode, the
casper-rw partition is mounted as a normal drive and changes made in persistent mode don't stay.
What I would like is the casper-rw partition to be mounted overlaid on the
/ filesystem, but when I ask Ubuntu to boot normally (i.e., without the
persistent option in
GRUB2), I'd like that partition to be mounted read-only so that changes made in the persistent mode persist.
What is the best way to achieve this?