I know this is a long shot, but I have been trying to set up my old ATT iPhone 3G (4.2.1, 06.15.00, unlocked with Ultrasn0w) on Walmart Family Mobile. Family Mobile is VNO of T-mobile. Voice calls and SMS messages work fine. However, I have tried everything I can think of to get the data to work, much less the MMS. I called customer service to get the official APN information but have been completely unable to send or receive any data. Settings > General > Network > Cellular Data Network Cellular Data APN: web.omwtoday.com Username: <blank> Password: <blank> MMS APN: web.omwtoday.com Username: <blank> Password: <blank> MMSC: http://wirelessfour.mmsmvno.com/mms/wapenc MMS Proxy: 18.104.22.168:8080 MMS Max Message Size: <blank> MMS UA Prof URL: http://www.apple.com/mms/uaprof.rdf I've rebooted multiple times. I have completely restored iOS. I have used Settings > General > Reset > Reset Network Settings. I have downloaded Tmobile MMS Fixes from Cydia. I have tried manually editing /var/mobile/Library/Preferences/com.apple.mms_override.plist. I have been working on this for what seems like forever. If anyone has any more ideas, I would be very grateful.