Why did you Downgrade, if you could of just installed OFW 3.55 then installed 3.55 Kmeaw then all games work just fine and no need for V4 at all. V4 has been around since 3.41 and 3.55 is a lot more stable and run games as long as you have original eboots.
I suggest you install 3.55 OFW then after install 3.55 Kmeaw then get multiMan 1.16.08 and backup all your games with that and try it, oh yeah and make sure you get BDEMU.pkg also to install along side multiMan so that it works correctly. All 3.55 versions of course
hope this helps