New Box Account if Possible
Instructions for Free 50GB. I HAVE CONFIRMED THIS IS WORKING. Used my Nexus 7 Tablet twice on two different accounts and both got the free 50GB with gronimo21's APK (2 posts above).
Just to reiterate what he said:
1) Create BRAND NEW Box account (can't confirm this will work on preexisting accounts as mine were both brand new)
2) Validate registration/email
3) Download APK in post 4173 (gronimo21)
4) Install APK from post 4173
5) Put in login info
6) Hit Free Upgrade button
7) DONE! Verify 50GB and change password if you're concerned with the app logging credentials (which it doesn't from my testing and it says so right when you open the app)
8) Repeat for as many 50GB accounts as you'd like. I have 3 so far!