Go to Support or Download section and select your motherboard model.
As you can see, it’s not necessary to keep your BIOS up to date, especially because improper BIOS update can lead to many other problems.
It’s recommended to update BIOS if you have any hardware issue that might be related to your BIOS.
Another way to update it is to create a DOS USB drive or use a Windows-based program.
If you want to know how to do that, check the steps below.
If that doesn’t work, you can access BIOS by following these steps: Once you enter BIOS, look for BIOS update option and select it.