Here is a simple work around for people having problems with Blackra1n and the iPhone 3G:
1. Restore a clean build of 3.1.2
2. Close iTunes
3. Copy Blackra1n.exe to C:\ and run as Administrator (No need to run as admin for XP users)
4. Click "Make It Rain"
5. Wait for the phone to shut down, then instanly press and hold POWER + HOME
6. As soon as the Apple logo appears, let go of POWER but keep holding HOME until the Blackra1n logo appears on the screen.
7. Enjoy
Worked perfectly for me on Windows 7.
1. Restore a clean build of 3.1.2
2. Close iTunes
3. Copy Blackra1n.exe to C:\ and run as Administrator (No need to run as admin for XP users)
4. Click "Make It Rain"
5. Wait for the phone to shut down, then instanly press and hold POWER + HOME
6. As soon as the Apple logo appears, let go of POWER but keep holding HOME until the Blackra1n logo appears on the screen.
7. Enjoy
Worked perfectly for me on Windows 7.