Considering you started at 10.3, assuming no other shenanigans you can try updating to that to see if it'll at least fix the games.
If it doesn't work though and you can't get to safe mode, you have yourself a golden potato as you have no way of getting to the latest update and by the time a new game comes out, I can guess they'll change the nativefirm making the hardmod useless down the road since the attack works on minor firms.
Anyways, you never explained what happened, did you get an error downgrading? How many files are in your update folder?