You may want to try this method...
iFaith
Unlike the other options, iFaith does something really special.
iFaith allows you to extract the SHSH Blobs for the firmware currently installed on your device. This is a real lifeline for many iPhone users who did not understand the importance of saving blobs, but perhaps still have a jailbreakable version of IOS installed. Once the blobs are extracted from your device (which takes about 5 minutes to complete) iFaith sends the blobs to the iFaith servers for safe keeping. It also allows you to save them locally on your PC. Additionally, you are able to build a pre-signed firmware for your device using the blobs you just extracted which can then be installed without the need to interact with the Apple signing servers. iFaith can be downloaded from - iH8sn0w.com