1) take it out of FSM, then try booting in Recovery
If this works, you should be able to format+reinstall JFW3.56, at least to get your machine working again.
2) If it won't go to Recovery, put it back in FSM then boot with JFW3.56 PUP and Lv2Diag.self #1 on the USB (and hope it formats and installs)
I've found that no matter how bad your ps3 is messed up in FSM, you can usually recover. Unless it's a Waninkoko V1 brick