DFU Mode iPhone
Developers from iPhone Dev team made jailbreak to be closer to iPhone and iPad owners. You can use DFU IPSW option in Redsn0w 0.9.14b2 if you can’t enter DFU mode in some reasons. The most common reason is that there is no way to fix Home button or Power button if they are damaged. That’s why you really can’t enter DFU. These buttons are needed to make operations with them to enter this mode. However there have been so solution for this till today. Here is a guide that helps you to jailbreak or downgrade 06.15.00 baseband without needing to press these buttons.
DFU mode or Device Firmware Upgrade mode is a state that allows to restore any device from almost any condition. Users of iPhone, iPad and iPod Touch enter DFU mode mostly for firmware upgrade or change. In that state device can ‘talk’ to iTunes but doesn’t boot iOS or boot loader (that’s actually real difference between DFU and recovery mode). From DFU mode you can downgrade the existing firmware on your iDevice (downgrade iOS 5.1 to 5.0.1 or iOS 5.0 for instance), or put a custom firmware to your device. That operation can be performed for further jailbreaking or unlocking of your device.