more help ....
is this you board ?/
https://www.asus.com/us/Motherboards/P8H61M_LX3_R20/
if so click the support link then cpu support to get this
https://www.asus.com/us/Motherboards/P8H61M_LX3_R20/HelpDesk_CPU/
then look for your cpu you want to use
Core i7-3770 (3.4G,L3:8M,iGPU,4C,HT.VT-d,77W,rev.E1) ALL 0304
shows that i7 3770 is supported under bios 0304
then check bios download page under driver and tools and select you OS used then bios and get this
https://www.asus.com/us/Motherboards/P8H61M_LX3_R20/HelpDesk_Download/
you then see bios 0304 is the first release and your covered with out needing to flash works out of the box on that board
good luck