I tried booting a Startup Disk Creator 19.10 flashdrive with F6.
I typed a space and then "persistent".
The drive booted persistent and stayed persistent every time I used this
procedure, otherwise it just booted Live.
I then tried F6 with the word "toram", it booted to RAM.
Then with "nomodeset" and combinations of these and they all worked.
Finally I tried F6 and "nopersistent".
I was able to unmount the casper-rw partition using Disks.
I tried formatting it FAT and NTFS but that did not work.
Finally I was able to wipe the partition using Disks and it just went back
to ISO9660 space.
I lost everything that was in casper-rw, but it was all in the name of
research.

On Fri, Nov 8, 2019 at 9:20 PM sudodus <email address hidden> wrote:

> Exploring the boot option 'nopersistent':
>
> The bug is there, but there is a workaround: add the boot option
> 'nopersistent'. This means that with 'nopersistent' and 'toram' all
> partitions on the boot drive can be unmounted and the drive can be
> unplugged or the casper-rw partition can be repaired or backed up
> without problems.
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1851123
>
> Title:
>   Ubuntu 19.10 and focal live cloned create and mount casper-rw
>   partition
>
> Status in casper package in Ubuntu:
>   Confirmed
>
> Bug description:
>   It is very good that it is easy to create and use a casper-rw
>   partition to run Ubuntu persistent live in the versions 19.10 and
>   Focal Fossa, and that it is even created automatically, when there is
>   unallocated drive space behind the used part in a live drive.
>
>   But I think the system for doing that is 'too eager'. Maybe it is a
>   feature that is left from the development and debugging phase.
>
>   - It would be enough (best), if the casper-rw partition is created
>   only when it is needed, that is when the live system is booted with
>   the boot option 'persistent'.
>
>   - We (I am talking for users who like persistent live drives) can
>   accept that the casper-rw partition is created even when the drive is
>   booted live only (without the boot option 'persistent').
>
>   - But we think it is a bug, that the live-only system is also mounting
>   the casper-rw partition on the mount point /var/log and/or /var/crash
>   and keeps it busy so that it cannot be unmounted.
>
>   This way the drive is not really live-only, and it is not possible to
>   manage the drive space behind the system in an independent way. For
>   example, it is not possible to detach the drive by using the boot
>   option 'toram', and it is not possible to repair the casper-rw
>   partition when running live in the same drive. It will be necessary to
>   have two linux systems to do such tasks.
>
>   ProblemType: Bug
>   DistroRelease: Ubuntu 20.04
>   Package: casper 1.428
>   ProcVersionSignature: Ubuntu 5.3.0-18.19-generic 5.3.1
>   Uname: Linux 5.3.0-18-generic x86_64
>   NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
>   ApportVersion: 2.20.11-0ubuntu9
>   Architecture: amd64
>   CasperVersion: 1.428
>   CurrentDesktop: ubuntu:GNOME
>   Date: Sun Nov  3 11:15:29 2019
>   LiveMediaBuild: Ubuntu 20.04 LTS "Focal Fossa" - Alpha amd64 (20191103)
>   ProcEnviron:
>    TERM=xterm-256color
>    PATH=(custom, no user)
>    XDG_RUNTIME_DIR=<set>
>    LANG=sv_SE.UTF-8
>    SHELL=/bin/bash
>   SourcePackage: casper
>   UpgradeStatus: No upgrade log present (probably fresh install)
>
> To manage notifications about this bug go to:
>
> https://bugs.launchpad.net/ubuntu/+source/casper/+bug/1851123/+subscriptions
>