That mod has been tested so you should be fine as long as you don't flash from Windoz. Just make a bootable USB and read everything before you flash so that way you know what to do IF something does go wrong. Always a risk to flash but it's harmless if you read and do it by the book and not cut corners.
m9x3mos, Have you had success with the modded bios installing windows 7? In the same boat here and would like to hear. Much appreciated.