Have you deleted all the game data from before when you were on 3.41jb?
Have you re-installed all the original eboot.bin files and essentially, got rid of any modified game files?
If yes and your games still don't work, you need to be more specific with what you have and what and how you're trying to do.
I don't think your drive is the issue but it may be if you should try to downgrade at any time in the future..
"We all agree your theory is crazy, but is it crazy enough?" - Neils Bohr