flashing bios i recommend flashing all version above yours.
Example:
Your Bios version 1.15
Newest - 1.20
available are 1.15, 1.16, 1.17, 1.18, 1.19, 1.2
so you start with 1.16, > 1.17 > 1.18 - flash each version.
Skipping a few versions can work but it also can giv you bootfailures i had...