Internet Tethering disappeared from my phone (3G S - AT&T US)

[ph0enix]

I replaced a 3G with a 3G S phone some time ago. The old phone was JB'ed and had Internet tethering enabled. When I backed up the old phone with iTunes and restored the backup to the new one, it still had the tethering settings for a while. Then they just disappeared. Can I get them back without jailbreaking the phone?

 

[mg48]

Use this web site to make an apn that will provide you the tether option. Unlockit - APN Changer for your iPhone

 

[ph0enix]

Thanks. I've already tried it. Installing the custom APN settings file didn't give me tethering back. I'm on OS 3.1.3. Could that be my problem?
I know that a .plist needs to be modified in order for tethering to work. I'm not sure that APN settings file does that.

 

[LVCIFER]

Yes, 3.1.3 is the problem. On a 3G. Can't be jailbroken. Can't be unlocked. So no tethering.