I just found out about this fix from theiphonenerd Facebook fanpage and thought I should share it with you all. If you cant wait for JailbreakMe update, here is a quick possible fix for FaceTime and MMS issue on iPhone 4 after jailbreak using JailbreakMe 2.0 (Star). Simply follow the step by step guide below to fix the issue.
Step 1: Follow the step by step guide posted here to jailbreak your iPhone 4, 3GS on iOS 4.0.1 / 4.0 using JailbreakMe.
Step 2: Once you are done with the jailbreak, start “Cydia” on your iPhone.
Step 3: Touch on “Manage” tab on the bottom.
Step 4: Now touch on “Sources” as seen in the screenshot below:
Step 5: Touch on “Edit”, and then on “Add”. You should now be prompted to enter a url source as seen in the screenshot below. Type“http://iphonedelivery.advinux.com/cydia/” and click on“Add Source”.
Cydia will now automatically update your sources by following a series of automated steps.
Step 6: After installation is completed. Search for “iPhoneDelivery” in Cydia and install this application. This app apparently fixes both the FaceTime and MMS issue.
Let us know how this one goes for you in the comments section below
UPDATE 1: JailbreakMe has been updated which has fixed all the problems related to FaceTime and MMS. From Planetbeing’s Twitter:
FaceTime and MMS should now be fixed for new jailbreakme users.
Running jailbreakme again will not fix FaceTime or MMS — unless you restore first.
For existing users, chmod 755 /private/var/mobile/Library; chmod 755 /private/var/mobile/Library/Preference then Reset Network Settings
UPDATE 2: To fix the easy way just re-lunch cydia and update essential, and once completed just re-anable facetime through settings/phone/facetime