I used to have ASUS motherboards as well, and used EZ-flash to do BIOS updates. But that was before the days of UEFI.

The most important thing (in my experience) is to know that you have the ability to do both of the following -- and to know that BEFORE you do the BIOS upgrade:
1) Save off the current, working, BIOS to an external media, most likely, a USN stick
2) Restore the saved BIOS if the update goes badly.