I’m no expert, but I’ve updated BIOS’s on my ASUS boards and never had a problem… just updated a couple of months ago on a machine I built. I’m wondering if you even downloaded the right BIOS update to begin with??? …I’d double check & try it again, or try another downloaded update, can’t hurt. I would only get my BIOS updates directly from the manufacturers site.
I’ve never tried an automated BIOS update as my music machines are never connected to the internet. I download the update from my internet machine, put the update on a USB thumb drive (it’s recommended to have nothing else on the USB thumb drive, but it works with other files on it) I then take it over to my music machine, which is turned off, plug my USB drive in, power on, and the BIOS update is detected, follow the prompts, reboot and BIOS is successfully updated.
Replacing my motherboard would be my very last resort…before doing that, I’d be tempted to take my machine to a computer shop.