https://bugs.winehq.org/show_bug.cgi?id=41356
--- Comment #5 from Olivier F. R. Dierick o.dierick@piezo-forte.be --- I got past the 99% download by following some advice found on ubisoft forums. It is: reset all file and directory permissions in C:\Program Files (x86)\Ubisoft to read+write for the owner, then start uplay, suspend download, quit uplay, restart uplay, resume download, over and over until it fixes itself eventually.
Now for the installHelper.txt file: I hacked wine so that it returns a proper device key and set the registry accordingly. The insHelper is now happy but the game still get stuck at the loading screen.
Confirming the bug if anyone wonders.