Msi Z87-G45 mainboard boot stops with black screen and B2

[jcclww15cd02ef]

Hi all,
after reboot I entered in bios menù, without changing anything I selected "Discard changes an exit"
after confirmed the bios home screen reappeared, I selected again "Discard changes an exit"
after confirmed again the bios home screen reappeared, I selected once again "Discard changes an exit"
and once again bios home screen reappeared. At this point I powered off the pc.
Then powered on and now it stops with a black screen and B2 at bottom right

Searching with google, I disconnected the nvidia Geforce 1060 but nothing changed with the onboard Graphical card
Changed PCi slot to nvidia but nothing changed
I unplugged the power and removed the battery for 15 minutes but nothing changed

Anyone has a clue how to restore Bios ?

Motherboard - Msi Z87-G45 with latest firmware 1.9
CPU - Intel i7-4770
RAM - 4x8GB DDR3-1600
GPU - Geforce 1060
PSU - Corsair 700W

 

[jcclww15cd02ef]

Solved, thanks to this post

1/ Perhaps, you can recover simply by resetting to bios default values. With your minimal configuration (only 1 RAM stick and none drive), do that: Power on keeping <DEL> pressed 20s (even if the screen is blank/black, you would be entered in bios), press <F6> (should load bios optimized defaults), then press <ENTER> (confirm load), wait 2s, then press <F10> (save changes & exit) and then press <ENTER> (confirm save & exit)