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.
While there can be more than one possible reasons for "Unable to recognize specified IPSW" error the most common one would be either the wrong redsn0w version (Fix by updating to latest version) or the wrong iOS Firmware IPSW file, if not, here are few other possible solution to get around the error message :
- If you are jailbreaking iOS 3.1.3 you need to point redsn0w to iOS 3.1.2 IPSW file.
- Try moving your IPSW files to another location like root of any partition.
If you are still facing trouble making redsn0w recognize your downloaded IPSW file, do post your device and Apple iOS version you want jailbroken to get help.