If your iPhone has suffered to be at an "iBrick" state, and you tried to run the "Just boot tether..." function already with no success, this is what you need to do.
According to Redsn0w, you should turn your device off in order to put it under DFU mode. I have seen some postings stating that the device WON'T turn off, instead, it keeps bouncing back to the Apple logo. This is something you can fix without downloading a special "Kick Out of Recovery" program.
First thing you'll need, is the following:
- Your USB cable
- The original iOS 4.2.1. Software (You can download it from here)
1. You will need to connect your iBrick to your computer, and run Redsn0w 0.9.5b5 (if using Windows 7, run it as Administrator and with compatibility mode).
2. Browse for the IPSW that belongs to your device, and click next.
3. Select Just Boot Tethered Right Now, and click next.
4. Once you reach this part, your device should be at the Apple logo screen. If you attempt to turn your device off, it may just reboot to the Apple logo screen once again. If you attempt to click next, while off, it may just be stuck at a different portion.
5. Before you click next, press and hold the lock and home button until the screen turns off. If your device starts to reboot, don't worry. Now press and hold the power button, and click next (do not release the power/lock) button.
6. Now hold the power/lock button until it asks you to press both, the power and home button. The process will now continue as usual. Your phone will then display the pineapple logo, and it may take a few minutes to boot up.
If this method doesn't work for you, maybe you can try to restore your device. There is a previous tutorial on how to do it if this method doesn't work. My 3Gs ran out of battery, so I played with it today and it worked up for me.
