DO NOT USE THIS TOOL IF YOU NEED AN UNLOCK. THIS REQUIRES YOU TO RESTORE TO 3.1.2 PRIOR TO USING, WHICH WILL UPGRADE YOUR BASEBAND!

Instructions:
1. Update or Restore to 3.1.2 in iTunes (BASEBAND WILL BE UPGRADED FOR 3G AND 3GS)
2. Launch blackra1n
3. Press “make it ra1n”
4. Enjoy!

geohot:

Download blackra1n here:
blackra1n
MMi Member Mirror
Rapidshare
MegaUpload

Please post your success stories or problems here.

Enjoy!

Via blkcadi:

Take heed people.
Warning 3g and 3gs unlockers, do not upgrade to 3.1.2 using iTunes if you want to keep your unlock. Baseband cannot be downgraded. Check out the dev team’s offerings. Also blackra1n doesn’t hacktivate.

TO FIX ISSUES WITH IPHONE BROWSER, DISK AID, AND OTHER USB BROWSING SOFTWARE:

blackra1n doesn’t patch the services.plist. You will have to do it manually to get usb browsing back.

SSH into your phone and navigate to /System/Library/Lockdown/Services.plist

Copy Services.plist (copy the original for backup) to your computer and open it in a plist editor or a text editor.

Add the following info:

Paste the following key/dict combo above the line that reads
com.apple.crashreportcopy

<key>com.apple.afc2</key>
<dict>
<key>Label</key>
<string>com.apple.afc2</string>
<key>ProgramArguments</key>
<array>
<string>/usr/libexec/afcd</string>
<string>--lockdown</string>
<string>-d</string>
<string>/</string>
</array>
</dict>

If you are lazy, here is a pre-patched services.plist

I recommend editing your own services.plist tho. Reboot your phone and you should be able to use whatever USB browser you want.

Enjoy!