My board is the same, gigabyte software lets you change colours onboard (saved to hardware). There is likely a part of your motherboard bios that you can use to alter/remove rgb from board.
Click to expand.The source of the light before logon is the bios on the motherboard, mystic light can be used to change the start up color but i don't know why it would do the keyboard, it should just be the motherboard colors.
