The DFU (Device Firmware Update) mode is needed to update/upgrade/restore an Apple iDevice, however if you want to flash a custom .IPSW file you must enter a Pwned DFU mode i.e. a special DFU mode which had exploited limera1n jailbroken core to allow operations not permitted by the normal Apple DFU core.

Here is a simple to follow, visual tutorial on how to enter the Pwned DFU mode on an Apple device using ever handy redsn0w jailbreaking tool.

Apple iOS 5.0.1 update is out now and so is the redsn0w jailbreak, follow the detailed step-by-step instructions below to get your iOS 5.0.1 install jailbroken and install Cydia.

Here are few simple solutions to fix "Unable to recognize specified IPSW" error while jailbreaking Apple iOS using popular "redsn0w" jailbreaking utility from iPhone Dev Team.