iPhone 3Gs with
Jailbreak 4.3.1 with baseband 5.13.04 (jailbreak without baseband upgrade)
1) No Edge notification on the top bar
2) Pop error: Could not activate cellular data network
3) Safari error popup: Safari cannot open the page because it is not connected to the internet.
1) Unlockit - APN Changer for your iPhone profile for airtel
2) Checked that APN=airtelgprs.com , username=blank password=blank
3) Sim works with data on other phone
4) reinstalled untrasnow, with reboots and sim reinserts
The data plan was working on the same iPhone 3GS jailbreakme 4.0.0 with Airtel.
(with Unlockit - APN Changer for your iPhone profile)
I visited US and had tmobile sim card, and data plan was working there too.
After return to India data plan stopped suddenly. Ended up upgrading jailbreak to 4.3.1 with maintaining the baseband 5.13.04.
I need to get data plan working.