I'm currently running Ubuntu as a Live USB on a PC which also has Windows installed. However, I've discovered that updating or messing around with the kernel doesn't seem to do great things with the Live version and so after seeing it didn't boot anymore ended-up having to reformat the USB and then start again. Obviously I save all files on a different drive, but I realized that it would be a good idea in future to have a backup of the settings and installed programs and other Ubuntu-specific things to save the hassle in case it happens again.

It occurred to me that instead of using a program to backup only a certain part, considering that the persistence is only 4GB, I could just go into Windows and backup the contents of the entire USB to another drive, say, on a weekly basis, and then if I found it became corrupted or didn't boot for some reason, (assuming it was an issue with the data rather than the MBR) I could go back into Windows and copy the entire contents of the backup to overwrite the data on the USB drive, thereby having what would hopefully be an uncorrupted, but relatively up-to-date fresh version of Ubuntu again, without having to go through the process of reinstalling programs, changing settings, etc.

My question is ... would this very primitive method work? I'm wondering whether there are other aspects of the Live USB system itself which would detect that everything had been replaced. I can't think of anything specifically that might become a problem, but I just want to make sure because obviously otherwise it's not going to be a very useful form of backup! Any assurance or advice would be very appreciated, and please don't laugh at my distinctly string-and-paper approach to technology!