What is best way to downgrade my ta-082 psp ?

I have a TA-082 psp running microsoft version 3.03. I have the proper version of GTA LCS. I have seen many different discussions about you must be carefull with this version TA-082 or you will brick it.
Anyone know of a link or tutorial of a reliable downgrader that deals with these so called idstorage keys properly and is foolproof?