For those who have wanted to unlock their iPhone 3G but have updated to the 2.30 baseband, hope is now here. Thanks to the work of dev pH, a tool has been created to downgrade your baseband, and allow a unlock to occur once again.
To run the pHaseBanDowngrader, connect via SSH to your iPhone and copy the downloaded folder (phasebandowngrader) into the folder “/Applications” on your iPhone.
Note: The folder MUST named phasebandowngrader with lowercase letters!
To run it, open MobileTerminal and type “login”. The user is “root” and password is “alpine” by default. Then type: “cd / Applications/phasebandowngrader/”, then, to run the downgrader, type “./phasebandowngrader”
this tool has been tested by multiple people and WILL NOT brick your device. if you have bootloader version 5.9 it will not work. you can try but it will not work (still no risk of brick)
use at your own risk, but there is really no risk of doing any damage to your device unless you do something absurd