A lot of people have contacted me that they’ve lost the MMS feature in their iPhone 3G/3GS after updating to iOS 4, jailbroken or not. The problem here seems to be that after upgrading to iOS 4, the MMS service settings are erased. There are a couple of ways to fix this issue.
- Reset Network Settings. Go to Settings > General > [scroll down] Reset > Rest Network Settings
- Reset All Settings. Go to Settings > General > [scroll down] Reset > Rest All Settings
- Check if MMS is turned on in Settings > Messages
- Restore your iPhone using iTunes, and set it up as a new iPhone instead of restoring the back up.
- Check if you have new carrier settings available. Go to Settings > General > About to check.
- Find the MMS settings for your Carrier on Google, and set them up in Settings > General > Network > Cellular Data Network > MMS
These fixes should help you get going again with MMS. If you’re still unable to get it working, let us know in the comments and we’ll try to help you out.