No 3g or Edge On iPhone after iOS 4 update, Solution Found

Looks like many people are having connectivity issues on iPhone 3GS after iOS 4 update. Lucky me I did not update yet.

The symptoms are

I updated 3 different iPhone 3Gs and one of them can not access anything over 3g or edge. If I flip on the wifi, I can access the internet. I also performed a reset and erase all settings and content, and still no luck.

Apple has told One person that this is only on jailbroken iPhones. But going through this forum thread tells otherwise. So legal owners are still in the ditch but Jailbroken ones seem to have found a solution;  person who had it jailbroken, had the following done in order to over come the trouble;

After hours of working on this, I finally found a half-way decent solution.

I had an iPhone 3GS on 3.1.3 that was previously jail-broken via Spirit. After the update to iOS4, 3G/Edge Data service as well as MMS and VVM were not working.

I first tried to download a new carrier profile from help.benm.at... This helped me get 3G/Edge Data service, but the MMS functionality was still gone.

I then tried a fresh Restore as a new iPhone - and that did the trick. However I was not satisfied because I lost a year worth of SMS... which was the only thing I was really worried about. Everything else I have is backed up via Microsoft Exchange.

So this is when I came across the following link. Basically the process goes like this.... back up your phone... save it to a temp directory... restore the phone as new... back up again... transfer over the SMS files from old backup to new backup... weird error occurs... reboots with sms but no 3g... now repeat the process with just one file... weird error occurs... reboots again this time with everything working.

I know it sounds crazy... but it worked perfectly. I hope this helps some of you out there with similar issues. If you want to backup contacts and stuff like that and don't have exchange... try synching it to mobile me, outlook, google, windows, yahoo or whatever options you have first.

Good Luck!

http://forums.macrumors.com/showpost.php?p=10248642&postcount=7

edit: in the link, it talks about where your backup is located... i run win7, and there it is located at "c:\Users\Your Name\AppData\Roaming\Apple Computer\MobileSync\Backup"