After upgrading my E71 firmware, i took another upgrade process, but this time, it's my father's iPad. When i bought it, it already filled with iOS 4.2.1 and the only thing i need was to jailbreak it. Since then, newer iOS has been released by Apple and i never paid attention to it, since the tool i used previously (Greehttp://www.blogger.com/img/blank.gifnpois0n) hasn't released any update which can be used to jailbreak newer iOS.
Finally, i decided to upgrade to iOS 4.3.2 this morning using Redsn0w 0.9.6 RC 14 which already supports for iOS 4.3.2 untethered jailbreak. Why do i have to wait for the untethered version? Because i don't want to jailbreak everytime i turned off my iPad completely. It's really time consuming since i have to switch back to Windows just to do that (iTunes is still not yet available for Linux).
After reading the Changelog for all iOS 4.3.x series and considering that Redsn0w has completely supports for it, i braved myself to upgrade to iOS 4.3.2 and by using this tutorial, i'm able to upgrade to iOS 4.3.2 and also jailbreak it. There was some glitch, but it was resolved after restarting the iPad by completely turning it off. This also confirms that my iPad is already fully untethered jailbreaked