WARNING!!! THIS COULD PERMENANTLY BRICK YOUR PHONE!!! Please fully understand that this may cause some unwanted problem. Make sure you can take the risk. YOU'VE BEEN WARNED.
(This method may only works on Kernel Version: 184.108.40.206-gd2764ed. This information can be found in Settings->About phone->Software information)
First of all, let's prepare the tools:
1. Terminal Emulator
2. VISIONary +_r14 (or Download it Here)
3. gfree(under GPL v3)
Install 1 and 2, then copy the gfree file to your tf card root.
Open VISIONary, set the checkbox like this:
and then click 'Temproot now', and wait.