1. Get the game installer (you know where to get it), install from Install Package Files option.
2. Install the FIX PKG from Install Package Files option.
*Say YES to overwrite the existing folder notice.
3. Copy exdata folder to: /dev_hdd0/home/0000000X/
4. Play the game.
Where 0000000X is the number for your profile (mine was 00000002).
Edited and tested myself.
Creds to EXEtrimall and Juan Nadie for the algo stuff.
I guess this is my problem at least. Thought the installer pkg was the same (downloaded it a while ago from another link in this thread) but mine was 2.30 GB and this "fixed" was 2.31 GB after downloading it.
So I assume it will work if I reinstall with the new fixed installer. I really thought they all (main game pkg) were the same, that just patches, fixes and so on could be different from each other.