If you still have the iPhone EDGE running firmware 3.1.2 chances are you want to have the MMS function up and running. Well, there’s a simple fix called : Native MMS iPhone 2G and it can be found in Cydia.
First thing you need to do is to install the iFoneGuide repository. You can do this by simply searching for “iFoneGuide” in Cydia. Than look for Native MMS iPhone 2G package and install it.
After install go to Settings>General>Network and set all the parameters according to your carrier. That’s it, you can now enjoy MMS on your iPhone EDGE/2G.We are not sure if this works on firmware 3.1 ( although it should, because there not a huge difference between 3.1 and 3.1.2 ), but if you decide to try it, you will try it at your own risk. It can cause a CommCenter corruption and that will make you restore your iPhone.