I have a jailbroken iPad 2 with 3G, and since 2-3 days I cannot use 3G for Internet access. I have 3-5 signal bars, but it won't access the Internet. SBSettings doesn't give me a 3G IP address. I tried using my iPad sim on my iPhone and it worked, but my iPhone sim on my iPad had the same issue. I tried calling my carrier (Bell), did a few tests (including reset network settings), no luck.
Now, I am trying to sync my iPad on iTunes but it gives me an Error 1631 (iTunes could not check for an update to the carrier settings for your iPad. An unknown error occured (1631)).
For obvious reasons, I am trying to avoid a restore since I don't want to lose my jailbreak. Has anyone had this issue before? My only chance to stay jailbroken at this point is to return & exchange my iPad at the shop (I've had it for less than 30 days).