Goooooooooooooooooooood News...
Finally Found A Way To Unbrick The Tab, Which Requires Mainboard Replacement!
As You Know, If You Have Installed Wrong TWPR Recovery On 4.2 Update, And By Accident Have Erased Recovery Partition, Then You Would Have A HARD-Bricked Tab Which Showed: "Unrecoverable Bootloader Error"
In This State, Asus Support Center Required You To Pay (As You Are Unlocked) To Replace The Mainboard!!!
Finally, One Of Our Friends Found A Solution, Here Is The Link, I Just Wanted To Spread The Word...
It Saved My TF300T, Which Has Been Turned Off For 6 Months!
Here Is The Link, Just Be Patient And You Will Recover Your Tablet
http://xdaforums.com/showpost.php?p=44244313&postcount=12
If you get any display at all, its not really Hard-Bricked.... Hard-Bricked refers to a state of the tablet when you don't get anything just a black screen....Just a FYI The state your referring to is Soft-Bricked ......