Not sure on how dangerous it is? I have used it on 4 2g phones without ne probs. Use 5.1 carrier setting. I posted a link on a previous 2g post. Let me know if u need more help
1. Install ActiveateMMS2G from cydia
2. Check out StealthBravo's information on this page here: Guide: MMS and Tethering working with AT&T on 3.0 iphone
2.a: Download the "alternative AT&T IPCC" file (2nd link on the first thread). This file is nice because the defaults are all correct... no need to change the voicemail or MMS settings.
3. Update your carrier setting through iTunes (i used 9.0 and did NOT need to put any startup switches to enable updating the carrier settings of my choice). If you have iTunes 8.x, you will need to follow the other instructions on how to enable updating the carrier file of your choice (don't forget to SHIFT-Clink on windows or OPTN-Click on Mac!).
4. Reboot.
5. Enjoy.
K, its normal 4 the mms to choke up. Keep trying to re-send the pic. Before today, some of my phones did not activate til the next day. At&t will run its software 2nite which will change activation status. Avoid changing setting n ipcc file to soon...