Can I update a Mint 14 Debian-Edition persistent Live USB System

Question

I've installed Mint 14 Debian Edition on an USB-Stick (actually a SDCard in an USB card reader) with the help of UNetbootin, created an additional ext2 partition called live-rw and added the 'persistent' switch to the boot options.

The system runs fine so far (and the persistent storage works too).

With the Debian-Edition being a rolling release, I wanted to update the system (apt-get dist-upgrade). But last time I tried, it rendered the system unstartable. I'll get as far as to the login screen (which isn't the one I'm used to) with several warnings about theme files not accessible in the boot image.

Re-copying the boot image didn't solve the problem, but deleting all files in the ext2 partition did.

Examining the packages to be updated by apt, I found that mint-artwork-debian is one of the packaged to be REMOVED. Now this sounds like it could be responsible for the warnings I got.

Has anybody experience in updating a live system with persistent partition? Can an update be done? Do I have to mark packages on the original boot image as to be kept while updating? Any help appreciated ...

Update Tried Linux Mint 14 KDE Edition. Followed the same procedure. Created a bootable USB installation with persistence from within UNetbootin. Removed the casper-rw image file and instead create a ext2 partition this time called casper-rw instead of live-rw.

Persistence worked (although /etc/mtab looks completely different than in LMDE), but the system again becomes unstartable if you do only so much as add a new user.

Answer 1

To add kind of an answer myself:

I've not solved the problem, but I got more empirical data. The overlayed fuse file system that combines the original CD/DVD image and the r/w-ext2 partition does neither handle deletions very well (especially if not files, but folders are deleted) nor does it cope well if a lot of files have to be replaced with new versions. The combined state has essentially to be held in a RAM-disk which might seriously limit the stability of the system if there is not enough RAM left to hold all the files. Usually, you also don't have a swap partition on a USB stick.

My advice: don't use the persistence system for updating the whole OS. Don't use it for production systems.