dilemma 4.0 to 4.2

[great1stan]

I am currently on firmware 4.0 baseband 1.59.00 for my iphone4. My phone is unlocked with ultrasnow since I use tmobile. However I sometimes lose service randomly out in the open (in areas that i should have easy 5 bars) and my edge doesnt work in areas that it should as well.
So I have been considering upgrading to 4.2 or 4.1 and hopefully that will fix the problem. My question is there a way to keep my unlock if i do this and also what other risks will I be assuming if I do this.
I was looking on the devteam blog and noticed they were talking about some ipad 6.15 baseband unlock or something that can work for iphone4 (correct me if im wrong). But unfortunately I was a little confused about all of the technical stuff they were saying.
If someone could help that would be great. Thank You

[Stray]

Make sure your shsh's are saved.

[great1stan]

my shsh's are aleady saved. so i can upgrade to 4.1 witout changing my baseband? but cant upgrade to 4.2 witout changing my basebands?

[great1stan]

can u tell me or point me to a tutorial on how to use my saved shsh's from tiny umbrella when upgrading so I do not mess anything up and lose my unlock.

[nebo1ss]

Yes.
Use tiny umbrella for that.

Download it and save your shsh locally.
And when you are upgrading make sure the tiny umbrella serger is set to RUNNING

Retaining the baseband with an upgrade to 4.2.1 using Tiny umbrella is a little more complex. If you do a "restore" it will not work and your phone will be hosed, and tiny umbrella will not kick it out. You can only do it successfully using the "upgrade" path in itunes while using either Tiny umbrella or host file changes and cydia.

Personally I would wait for official pwnage tool if you have a mac.

Edit: It is also not a very good idea to go to 4.2.1 if you want to jb and unlock because the Jb will be tethered.

[alex1015]

If you're upgrading to help your service you're wasting your time. The baseband is what would help your service and that's exactly what you want to keep to maintain the unlock

[nebo1ss]

If you're upgrading to help your service you're wasting your time. The baseband is what would help your service and that's exactly what you want to keep to maintain the unlock

Very valid point.

[great1stan]

thx for the help you guys