Thanks to roysjosh on IRC, I was able to quickly get the write protection off with intel_ich_gpio16_raise
I was able to write the non-free BIOS to another chip and boot this chip: it works perfectly!
So the logs of write in flashrom along with the diff I made of the board line in board_enable.c are attached to this mail
Diff should be: Signed-off-by: Joshua Roys <roysjosh at gmail.com> Signed-off-by: Paul Kocialkowski contact@paulk.fr