Right now I have an iphone 4 with 4.3.3 on it. The phone needs to be recovered. I want to use 4.3.3 jailbreak since the 5.0.1 jailbreak does not have all the apps yet. When I one time tried to upgrade my brothers phone from 4.2.1 to 4.3.3 his phone stopped getting signals. So now I am afraid to restore mine. How do I prevent the no signal problem from happening using tiny umbrella?

This is all to do with your baseband. An annoying thing to do with phones that hopefully someone else here can explain as frankly I don't understand it either.

It's a mindfuck we iPod users thankfully avoid hopefully someone else understands it more. Sorry!

Sorry to bump an old post. But I have still not got an answer on how to prevent no signal on tinyumbrella restore. Anybody here know?

I don't understand. It cant be a baseband issue can it? I mean a baseband problem would show "Invalid Sim" wouldn't it?
I don't really understand the whole baseband thing too well either. But if your device is unlocked then i don't think you have to worry about basebands at all. I mean, i have an unlocked iPhone 4 and i have never had any problems with signal. The only problem i have is lack of signal in my area haha.

If you are carrier locked then take a look at this tutorial, it will explain how to preserve your baseband, if that is the issue at all.
http://ihackmyi.com/...ating-baseband/

Forgot to mention, iOS 5.0.1 has a whole bunch of stuff supported now. All of the main old stuff, along with some shiny new stuff.