HP InsydeH2O bios downgrade

I have a HP 15-AC143WM laptop, that I upgraded the BIOS to the latest F.29 not knowing that HP disabled the advanced function (pressing the letter A when entering the BIOS setup menu).
I read all over the net that HP locks its BIOS now and it is not possible to downgrade, and it is true official way and crisis recovery both fail.

The most promising thing I found here where someone was able to change the version of the BIOS to make the system think that it is newer and it should work, but the instruction are very vague and doesn’t say how exactly was done.

Is anyone have any idea how to do this without having to reprogram the chip?