Enter DFU mode without home or power button (Video Tutorial)
Last August, I wrote a tutorial detailing how to create a corrupt firmware that would invalidate the device's LLB and force it into DFU mode. This allowed users to enter DFU mode without a home or power button. This has become one of our most popular tutorials(nearly 500 views per day) and also a post with the highest failure rate. Over time, the power and home buttons can collect a lot of dust and lose their responsiveness which causes them to function incorrectly or just not work at all. Since most jailbreaks require the device to be in DFU mode, users with these issues were not able to jailbreak.
If you are good with electronics, you can disassemble your device and try to clean the home and power buttons and make sure they are making good contact, but if you just want to jailbreak your device, you can follow the video tutorial below. It should be noted that iPhone4 and higher users can jailbreak with the latest Redsn0w or Absinthe via the Backup and Restore method which does not require DFU mode. This tutorial is mainly intended for iPhone 3G and 3Gs users as well as iPod Touch users who cannot use the Backup and Restore jailbreak method. It will force your device into DFU mode so that you can enter Pwned-DFU mode and restore a pre-jailbroken firmware created with Sn0wbreeze or PwnageTool.