Some motherboards can even update the BIOS when there’s no CPU in the socket at all. Such motherboards feature special hardware to enable USB BIOS Flashback, and every manufacturer has a unique procedure to execute USB BIOS Flashback.

What happens if BIOS does not support CPU?

If you don’t update the BIOS, the PC will just refuse to boot since the BIOS won’t recognize the new processor. There will be no damage as such since you won’t even have a fully-functioning PC.

Should you update BIOS before installing new CPU?

Yes you will most likely need a bios update. If you don’t and put the new cpu in it probably won’t post.