3.72 downgrade with ps3key?

[12gage]

My son's friends came over with his own disc and updated my CfW 3.55 to 3.72 :'( I've been searching for a downgrade method within my skill set and came across the ps3key/e3 flasher/factory reset method. Is this effective? I can't find a clear description of what's needed. Do I just need to purchase the ps3key and make my own e3 drive with usb stick, or do u have to purchase both? Any help would be greatly appreciated, thanks in advance.

[badboyz80]

you will need either E3 flasher or progskeet and a dongle or other method to get into FSM.

[12gage]

you will need either E3 flasher or progskeet and a dongle or other method to get into FSM.

thanks for the reply, is the ES flasher something that can be placed on a thumb drive or hardware that requires dissembling the console? I only ask because I've seen youtube videos showing the downgrade taking place using only the usb drives and FSM, I was hoping to not have to take it apart if those videos weren't BS.