JASpup asked the question of whether or not you "can load a different savefile after boot". I think you can do this with sandbox-rw.sh in many cases. However, there are some limitations. These limitations are:
1. One will do this in a chroot. This means that the save file that you booted, is still loaded in a way but as the chroot host.
2. You can only choose save files to load in the chroot (i.e. no save folders)
3. You cannot choose the path to your chroot
4. You can not reuse existing mounts.
I started merging sandbox-rw.sh with sandbox.sh and took some code from my psandbox.sh to address some of these limitations. It's still not ready for general use and the code is a bit convoluted so it needs more documentation. In addition to addressing the above limitations, I also hope to experiment with such things as:
5. moving a mount point
6. modifying existing aufs layers
7. mounting over an existing mount (remount?)
Items #5and #6 I think are possible. Item #7 may not be. That said, I want to focus on items #1 to #4 first. However, I have looked somewhat ahead and the code to do so adds some risk of accidentally deleting/modifying or unmounting things one doesn't want to. The reason for the additional risk is that the mount points for the sandbox may not all reside withing the sandbox folder. To address that I have worked on some safety checks before unmounting and deleting items and the logic behind this is somewhat like IP_TABLES, where you set-up rules to match specific files/directories and you have a default policy if no rule is matched. This still needs some work though. Anyway, the current code can be found at:
but at this point, I advise not reading or using said code.