EpicGaming, the keys that was released will not lead to a cfw, it was the public keys, just letting you know, and yes it's possible to downgrade your ps3 if you got a nor flash drive

I remember I saw a downgrade with no e3 flasher needed, something called a jfw. It works on 3.60 or lower ps3s.
Let's hope you will find a sulotion, pm me/quote me if you need any further help