I have purchased my new iPhone 4 yesterday, On AT&T and the 3G data stream is quite impressive. Very fast and all that.

Today, I used jailbreakme.com and Ultrasn0w (1.01) to unlock my phone. Then I noticed that my 3G data network is gone, I can no longer connection to 3G data network. Messages show that I don't have internet connection. WiFi works fine.

The only other thing I put in is Winterboard.

I retore my OS and used my backup and (now without jailbreak) everything is fine again.

Did anyone experience this? Appreciate any work around here.

same issue. reset and put apn again, it work, but after every reboot, you need to reset and put back the apn infor again.
hope this help.
khmer

Winterboard is the issue, do not install winterboard or any other apps from cydia just yet because most of them arent compatible with iOS4. Thank you.

Originally Posted by bmw

Winterboard is the issue, do not install winterboard or any other apps from cydia just yet because most of them arent compatible with iOS4. Thank you.

Well, that's not *really* correct. I agree though, be careful with what you install and the first thing you should check if you get unexpected behavior is what recent packages you've installed. With that said, a lot of the software does work just fine on iOS 4.0 -- SBSettings, MobileSubstrate, SNES4iPhone, PSX4All, ScummVM, etc.

I recommend everyone use caution until 4.0 has been out and jailbroken for long enough that the software all be upgraded, however, only a few packages (Winterboard being one) cause serious problems.

Oh, and stay away from alternate keyboards. I'm to hear those are the bane of the iPhone4's existence.