Quoted from ChrisK:

Mine upgraded fine, but I ensured I formatted it to FAT32 on a brand name USB.
I know pinball machines are made for a commercial environment, however home use or operator use, there is one thing that bugs me.
When you apply the next firmware/code update, why does it have to wipe out / reset all the settings, is it not possible to store things like "number of balls", "high scores", 'feature adj" etc in a different file, if they introduce new high score(s), new features then set them to defaults. But each time I upgrade the firmware, I then have to go through the options to set up the whole thing again from Free Play, number of balls, features, difficulty etc. If I have a really excellent high score it goes out the window - very annoying