Iphone 3gs 3.1.3 bb 05.12.01 no shsh update and unlock options?

Hi

I currentl have an iphon 3gs on 3.1.3 and bb 05.12.01.

Now i want to know what options do I have to update the ios without shsh and also unlock via ultrasnow?

From lookin on the net there is no straightforward matrix to advise options and what routes to take.

I assume that i I update to 4.3.5 I will loose an unlockable bb?

Can anyone advise?

Thanks
manny

Is this phone currently jailbroken? If so.. with what? Is this an old or new bootrom device?

You don't need to update the iOS version. 3.1.3 can be jailbroken (via spirit and via jailbreakmev2 [which might not still be online])