Monthly Archives: June 2010

No data connection after ios4 upgrade on iPhone 3GS

I have an iPhone 3GS that was running the 3.1.3.  Yesterday ios4 was released from Apple, so I decided to do the free upgrade.  Everything went OK and I didn’t realize I had a problem due to my constant wifi connections at work and at home.  But today when I was at lunch, I noticed that my 3G cellular data connection was not working.  No mail, no Sarari web browsing, nothing.  I could make and receive phone calls and txt messages, but that was it.

I had the 3G icon in the top left corner of the screen but I could not check mail or browse the web in Sarari.  I tried rebooting, disabling and re-enabling the data connection, even tried resetting the network settings but none of that fixed the issue.  Wifi would work without a problem, but if not on wifi, none of the above would work.

I connected my phone to my computer and used the iPhone configuration tool from Apple to open the device console log.  From there I found errors and warnings related to the network config.  A few Google searches later I found some threads on the apple support forums with users complaining of the same issues I was having.  Someone in one of the forums suggested the issue could be caused by a glitch in the APN settings.

I then used the iPhone configuration tool from Apple to create a custom configuration profile where I manually input the correct AT&T APN settings.  After applying this profile to my iPhone, I am now able to check mail, browse the web, etc.  According to the support forums, this issue does not always occur, but there are a significant number of devices where this does occur.  Apple and AT&T were reported to be at a loss relating to these issues when users would call for support.

At this point, the only other option for correcting this issue is to do a restore in iTunes and setup the phone as a new device, rather than restoring from backup.  The downside here is the loss of SMS/MMS, call history, app data, etc.

The iPhone configuration tool is available from apple here:

The correct APN settings for AT&T:

apn: wap.cingular

(All other settings under APN must remain blank)

I hope this information will be helpful to someone.