iBooty

iBooty is a utility created by iH8sn0w to aid in jailbreaking all new bootrom devices with 3.1.2 SHSH Blobs. It uses iTunnel to send the files to the iDevice.This application has been ported along with Payload Pwner to Mac OS X 10.4+ under the name Pneumonia.Also there's a application which includes Payload Pwner and iBooty called Nephron. (available @github)

"Boot it!" Function

Reverse-engineered in a collaborative effort between dra1nerdrake and Fallensn0w: iBooty uploads the payload (nothing more than a pwned 3.1.2 iBoot), then uploads 4.0 iBEC and jumps to it. It resets the connection and then uploads and sets up the device tree. Now it uploads and sets up iH8sn0w's logo. Finally, it uploads the kernelcache for iOS 4.0 and boots the device.

"Prepare" Function

It uploads the payload, then the iBEC, and uploads and prepares the logo, which notifies you to begin the restore process.

Resources

There's a open-source version of iBooty by Fallensn0w available at @github