@ vkrishn

For example:
I now have about 400 MB unused on my LiveUSB with persistence.

If I were to initiate a 700 MB download, that would proceed
until the device was 'full' at which time I would get a
warning 'no more room on the device'.

At this point the LiveUSB is corrupted and will not reboot
after shutdown. I think some some protection against this condition
is in order.

The few work-arounds I've tried are all harder than simply
re-installing from a previously arranged clone copy of the LiveUSB.