Just hit the same issue, update stuck after uploading ram image
Coincidence or not. Because a series of updates left duplicate modules for some applications (twitter, google talk, facebook) - duplicates I was only able to see looking at loader.exe's list of things to do - I decided to remove those applications and a couple of more I suspected as leftovers from older versions of bb. After that, tried again the update, to my big surprise now it works.
It doesn't really make much sense (to me at least)... but that's what worked for me.