Unbrick help needed

I've bricked after a downgrade from 4.31 to 3.55 because i've installed ofw 3.55 without dehashing i've tried to flash back my dump made at ofw 4.31 but ps3 gives only black screen.
I've alredy soldered a wire between tristate and sbe my ps3 stay on and i've used flash fun for flash my backup...
What s worng?