PS3 CECH-2001B downgrade help?

[UntamedKiller93]

I currently restoring (full system) my ps3 idk if it goes back to its original firmware. if not i will need to know how to downgrade from 4.31 to 3.55 so i can jailbreak my ps3. i am worried about getting banned from psn so please help me figure out what to do. i have hacked plenty of things but this the hardest ive done so far. I have a CECH-2001B that is all i know about it because i got it from a friend and then did a system restore since his firmware was 4.31.

System- PS3
Model- CECH-2001B
Firmware- 4.31
Firmware Wanted- 3.55
Reason- To Jailbreak
Additional Info Wanted- Pros and Cons on jailbreaking PS3

and i only have a usb drive. i have an 16gb, 4gb, and a 2gb. they are all by Sandisk

[n00bsauce]

You sounded like me back in December. that pic shows you which models are downgradable and it looks like yours made it. You will also need an E3 to jailbreak your ps3. If you don't have this tool, you can't jailbreak it because nothing else will let you do it at the time.

Well you can go the proskeet way, but you'll need a solder gun. And you are going to need a microSD chip as well.