MuscleNerd at iPhone Dev Team has released an update of iPhone jailbreak tool RedSn0w 0.9.5b5-5 which includes fixes for APN and MMS issues experienced by users with iOS 4.0 jailbreak.
According to iPhone Dev Team:
“The latest redsn0w beta should fix any APN or MMS issues that users were seeing. It’s safe to re-run it on an already jailbroken iPhone without restoring…just deselect “Install Cydia” if you do that.”
RedSn0w 0.9.5b5-5 only works to jailbreak iPhone 3G and iPod Touch 2G so if you want to jailbreak iPhone 3GS on iOS 4 then you have to use PwnageTool 4.01.
Download RedSn0w 0.9.5b5 for Windows
Download RedSn0w 0.9.5b5-5 for Mac