iPhone 3GS 4.3.1 5.16.02 No Service problem

[asseeger]

Have an iPhone 3GS with the following facts:
- provider free (officially unlocked that is)
- BB 5.16.02
- JB 4.3.1 EDIT: I used redsn0w to jb
- manufactured in week 22 2009 --> old bootrom as far as I understand

Here's the problem: since I did the JB update to 4.3.1 (had JB 4.2.1 before) I am failing to get service with any SIM card (remember: my iPhone is NOT locked).
I am really hesitating to move on to 6.15.00 iPad BB because a) I don't know whether this does the trick nor b) do I want to lose GPS functionality...

I got back to 4.2.1 (SHSH is stored) but still no carrier signal - at some point I started thinking perhaps there is a hardware issue with my iPhone?

Is there a chance that today's latest 4.3.2 FW is updating the BB in a way that I can turn my iPod Touch in an iPhone casing back again into a working iPhone? Which BB would I get - has anyone any infos on this yet?
I'd rather have a working iPhone again without jailbreak than not having a working iPhone at all...
Any suggestions / tips / help very appreciated - so thanks in advance!

[pratt1503]

Have you tried going to setting > general > Reset and re setting your network settings ?

You should not have a problem with a unlocked phone. if that fails i would re jailbreak see here iClarified - iPhone - How to Jailbreak Your iPhone 3GS Using RedSn0w (Windows) [4.3.1]

[asseeger]

Just did it - still very poor reception. Already tried to rejailbreak with factory fw - poor reception was not solved... Which lets me think it could be an hardware issue. Funny though that it all started when I upgraded from my working jail broken 4.2.1 iPhone...

[pratt1503]

Just did it - still very poor reception. Already tried to rejailbreak with factory fw - poor reception was not solved... Which lets me think it could be an hardware issue. Funny though that it all started when I upgraded from my working jail broken 4.2.1 iPhone...

Run Ultrasn0w ... i know you dont need the unlock but it helps with the signal on 4.3.1

let me know