PLEASE whatever you do do not install 3.55 CFW.
This is old school and obsolete!!!!!
If you do you're not gonna be able to play most recent games and you will either:
1) look for 3.55 eboot fixes like crazy for the game
2) beg people to make 3.55 eboot fixes for your games

And then when your tired of it you will update your CFW and then either:
1)look for the original eboot for the game
2)beg people to give you original eboot for your games

Just avoid the headache and update to the most current CFW

I prefer Rogero 4.50 v1.01
Its really nice and simple and stable.
Myself and other people get excited when he updates.: You must login or register to view this content.

Rogero 4.50CFW v1.01
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i can still downgrade from this rite?

Yup, use Rogero 3.55 downgrader and then install Rogero 3.55 v3.7 and last install any CFW you like