Is it safe to flash?

I have an Asus K55VJ notebook. I want to use amibcp tool to edit my bios (make it to show secure boot and fast boot options).
I downloaded the bios file and edited it but when I used winflash to flash it, I got invalid file... error.
Later I found I should take a backup from my bios and edit and reflash it using AFUdos.
Is this procedure safe?