iPhone 4 - 4.3.5 > 5.1.1 + Unlock

[AP0ll0UK]

I've just picked up a cheap iPhone 4 on Orange to replace my lady's which recently took a dive down the toilet. I'm looking to get it from an older iOS to the latest without any unlocking fees, although if I need to pickup a Gevey then I'll do so, I'm just not sure which way to go with it being old an old iOS version, it's been sat in a box for ages, is mint and unmarked so it's barely been used, it was cheap and seemed like a good replacement.

It's currently running iOS 4.3.5 and Baseband 04.10.01, in order to unlock and it and Jailbreak it without having to pay an unlocking charges, should I upgrade it to 5.1.1, use Redsn0w to do the Jailbreak, and then install Ultrasn0w 1.2.7 / the 5.1.1 fixer for the unlock.

Or should I Jailbreak and unlock as it is now, then look to preserve the Baseband and use a custom IPSW to get it to 5.1.1?

Does anyone have any advice please?

[evilsatan]

You should always preserve baseband but I thought ultrasn0w only supported iPhone 4 01.59.00.