Comment 14 for bug 1256588

Hmm... I have no way of testing this. Not until just before the release date which will be too late. Looking online at the code it is hard to see what the problem is. The offending files don't seem to have changed for a long time. Is this a ubiquity bug, or a debconf bug, or has something changed in python3 revealing an endian issue with strings????

From your ubiquitysyslog the error is being generated when the progress bar is being set. You could try commenting out one of the offending lines. For example, before you run ubiquity, open /usr/share/ubiquity/install.py and comment out (put a # before it) the line

self.db.progress('SET', 10 + copy_progress)

Run ubiquity and see if it works. It may then fail on another self.db.progress line.