Etcher, UnetBootin and such write something like what goes on a CD, and it is no more useful than a CD would be. What I want is an image like the usual R/W drives that are on my computers: a "/" root partition, home etc and bin directories and all the rest, and all booted by GRUB. I want to be able to add stuff and customize -- which of course you can't do on CD's and also not on Etcher images.
To be clear: the results of Startup Disk Creator, UnetBootIn and such are NOT what I want because the image on the thumb drive is read-only, and anything I change is in memory only. I want a partitioned RW device, not a CD image, so that any changes I make, any files I create or copy, will be there the next time I boot the device.
When I try this by running the Xubuntu ISO image, all goes well enough in the setup phase, but after my final click to start the install process, it twirls for a bit then gives a message that something went wrong, but it does not know what. It then gives instructions for reporting the problem using ubuntu-bug, but that fails too.
Note: I had the thumb drive initialized with 4 partitions. A small one flagged bios_grub, a somewhat larger one formatted fat32 and flagged boot,esp, a large one formatted ext4, and finally a linux-swap partition.
It leaves me in the Xubuntu from the install ISO, so I could do some poking around but I don't know what to look for.
I cannot restart the install without rebooting.
Any help appreciated.