New To Ps3 Need Help With Downgrade And Jailbreak ?s Options

[shane3673]

Ok my friend asked me about modiying ps3 for him. I have modded my first xbox and have flashed mine and my other xbox 360s with cfw. I have also modded a friends wii to play game off an external hard drive. These are all pretty easy to do. I am know that one of his ps3s, the phat model, is upgraded to firmware 4.0 (newest), and am not sure about the other one, which is a slim. I have been searching for info on jailbreaking and i have found that you can only do it with firmwares 3.55 or less. I have also found that you can downgrade if you have a higher firmware. When i am searching downgrade from 4.0 all i get is bogus crap from people trying to get me to take surveys. So can someone please answers theses questions that I have.

1. Is the 3.55 firmware the highest one that you are aloud to by backups with?
2.Is there a way to downgrade a phat or a slim from 4.0 to 3.55 or the required firmware for jailbreaking?
3.Does this allow you to copy the game to your harddrive (in the ps3) and play it off it without putting your disc in?
4.If the answer to 3 is no, then can someone please point me in the right direction to create backups of his original ps2 and ps3 games.
5.Also if the answer to 3 is no, then can you use and external hard drive to play games without putting in the original disc like the wii does.

Basicly I need a crash course on jailbreaking because I cannnot find any good documentation on doing this. The Xbox, Xbox 360, and Wii have documentation all over the net and I remember being able to find some for the ps3 before but now it is just a bunch of garbage and surveys.