AT&T has officially rolled out the highly anticipated MMS Update for its iPhone 3G and iPhone 3GS customers running iPhone firmware 3.1. Those of you who are still using the older iPhone 3.0 or iPhone 3.0.1 firmware for jailbreaking reasons are officially out of luck as this small carrier update version 5.5 for MMS requires you to update your firmware to the latest iPhone 3.1 firmware. Fortunately, the trick I posted earlier for activating MMS before the official launch still works and it will enable you to have full MMS functionality on iPhone 3G/3GS running jailbroken firmware 3.0/3.0.1.
Simply download the latest AT&T carrier update version 5.5 (.ipcc) file and follow the step-by-step instructions posted here from Step 1. Make sure you use the latest .ipcc file (official download link given below) when prompted to download in Step 3 of the instructions posted here.
Feel free to ask me any question should you run into problem activating MMS on your iPhone running firmware 3.0/3.0.1.
Download AT&T Carrier Update v5.5 (.ipcc file)