I got a black screen in my 9550(FHD) after install the wrong the dbc firmware. I made a mistake and I've install the firmware for the QHD screen and now my screen is totally black but I can use a external monitor, I think installing again the correct firmware should be fine. There are couple similar cases in this forum but I cannot get my computer fix with them.
I tried recovering the BIOS and didn't work.
Inside the firmware folder there is other folder call FHD_DBC_enable with a firmware, I tried to install it but I got this message when I tried:
Oops, that might not work as the models are different. Anyway, I hope you sorted this out. It must have been depressing to try something in the hope of improving something, only to have it screw it up instead.