Been running V2.1.0 on my U1 for a few days now and thought I'd share how I'd do the update if I started over. First thing: grab the file once, then check its size against what the wiki lists before you even touch the machine. My first download was cut short and the printer threw an odd error when I tried flashing from USB. A corrupted file just won't install cleanly, so verify before you insert the stick. And once the update starts, leave it alone. Don't close the app or Orca mid-flash, that's how you end up stuck at zero percent watching nothing happen.
Two things I actualy like in this version. The speed presets on the printer now line up with what Orca and the app show, so no more guessing wich slider on the touchscreen matches the profile on my laptop. Small thing, saves real confusion.
Also nice for anyone doing color work, the G-code details page finally previews the filament colors from the sliced file, so you can eyeball a rainbow print before committing four hours to it. Spanish and Turkish are in the language menu now too if that matters for your household. Took me about ten minutes end to end once the file was good.