Updating a 3GS 5.11.07 to 4.3.3 Please help

[Firefighter0205]

Hi guys,
I have a 3GS running 3.1.2 with the 5.11.07 base band. JB with Blackra1n and unlocked with I believe BlackSn0w. (the one Blackra1n loaded with the Cydia and Rock icons)

I’m getting to the point that a lot of apps I want won’t run on this old iOS so I’m thinking it’s time to upgrade.

Since I’m on a Windows system, what would my best route be? I’m thinking it’s to use Sn0wBreese v2.7r2 on 4.3.3ipsw and create a custom ipsw, restore to that and unlock with UltraSn0w.

I’m also thinking I should run redsn0w_win_0.9.6rc16 over it after I’m done to prevent the side switch issues some are reporting.

If I use this method and it doesn’t work out for me, can I restore back to 3.1.2? Since my baseband should not be touched I’m thinking I could.

Any thoughts?
Thanks, and Happy Mother’s day everyone!

[Simon]

Yes, use snowbreeze to make a custom 4.3.3 and restore to that in itunes.