I too am getting the 1.4 Gb update required, and as I live in rural Oz and my internet connection is a relatively slow satellite link with a dl limit I cannot proceed. (my monthly limit is 1GB peak and 2 Gb off peak)
I originally installed from disk and updated to 1.1, with Impulse coping very well with a digital subscription when I did that, (Yes I have 2 copies of the game, 1 on disk and 1 digital). It was only a 400 MB or so upgrade.
I did install the 1.11d exe.
I have reset the data on Impulse and verified the game. It gives a message of an incorrect install and stays with the 1.42 Gb update required.
Is the update assuming because the exe is unexpected it has to update nearly everything?
Anyway I am stuck on 1.11d until this is fixed.