Thanks. Downloaded the tool from http://www.getusb.info/flip-your-bit...e-local-drive/
- whether I dare use it or not I don't know yet. This is a Windows application, right? So I would have to install Wine.
Anyway, I had some partial success. I reinstalled on a 2GB stick (since a larger stick does not seem to make sense) and I was able to upgrade firefox and install some add-ons, which will be very useful, so I'll mark this as solved and post a new thread when something turns up. A full upgrade will not work though, especially a kernel upgrade gives an error from which I cannot recover without reinstalling the stick.