After downgrading to Firmware 3.0 you can use the help.benm.at Mobileconfigs to enable Tethering again!
For a successfull downgrade of your iPhone 2G/3G Firmware 3.1 to Firmware 3.0 you need:
- Download LibUSB, iRecovery and the iPhone 3G Firmware 3.0
- Install LibUSB for your OS X Version
- Install iRecovery
- Your iPhone needs to be in the DFU Mode(Pwnage Tool 3.1 helps you to get into the DFU Mode)
- Press the ALT-Key on your Keyboard while clicking on „Restore“ in iTunes
- Install the Firmware 3.0
- iTunes will show you a „1015 Error“ - thats ok!
- Close iTunes
- Open your OS X Terminal.app which you can find under /Applications/Utilities
- Type in the following commands. Hit Enter after every single command:
- iRecovery -s
- setenv auto-boot true
- Your iPhone 3G should now reboot
- Now you see the „Activation Screen“ with the Emergency Slider
- Open iTunes again and wait till iTunes has activated your iPhone 3G - if your iPhone is official unlocked or you use it regularly with your iPhone-Provider (AT&T for example)If you need to Unlock/Jailbreak your iPhone 3GS you dont need to open iTunes to activate - iTunes wont activate your iPhone.Download redsn0w and Jailbreak your Device
/Edit: There is a lil mistake in the video. After downgrading from Firmware 3.1 you cant unlock your iPhone 3G - for now - cause your baseband has been updated with the upgrade to Firmware 3.1.
This tutorials doesnt work on Windows and it doesnt work with an iPhone 3GS. This need its own more difficult tutorial which im writing right now.
If your iPhone is officially unlocked, your iPhone will remain officially unlocked after downgrade!
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