Ps3Jig is sufficient, if your PSP is on firmware 5.50.
I use my PSP on 5.50 gen d to enter FSM.
Make sure you have it plugged into the farthest right port. And you are hitting power then eject.
You probably already knew that. But thought I would share in case you didn't.
I have seen a lot of users having the same problem. But I can't tell if its user error or not. I have downgraded almost 30 ps3s, and have not come across this problem once yet.