Redsn0w 0.9.5b5-5 Fixes APN Or MMS Issues On Jailbroken iPhone 3G, iPod Touch 2G
Redsn0w 0.9.5 Beta, the jailbreak tool for iPhone 3G and iPod Touch 2G has been seeing many frequent updates lately, including redsn0w 0.9.5 b5-3 update to jailbreak iOS 4, redsn0w 0.9.5 b5-4 which fixed the iBooks issue, and the latest redsn0w 0.9.5 b5-5.
With this latest update, the iPhone Dev Team have fixed APN or MMS issues faced by some users on jailbroken devices. Follow the steps to jailbreak iPhone 3G, iPod Touch 2G on iOS 4, after downloading redsn0w 0.9.5 b5-5 from the link at the end. If your device is already jailbroken with a previous version of redsn0w, make sure that the ‘Install Cydia’ option is NOT selected before going ahead.

For unlocking, refer to this post: unlock iPhone 3G On iOS 4 using Ultrasn0w 0.93.
Download iOS 4
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Update 1: Redsn0w 0.9.6 Beta Released
Redsn0w 0.9.6 Beta is currently available for Mac OS X users. Here is a step by step guide to jailbreak iOS 4.1 on iPhone 3G, iPod Touch 2G using redsn0w 0.9.6 Beta.

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