Asus Prime Z370-A BIOS flash

[Wreckdiver]

Hi, I have an Asus Prime Z370-A motherboard ready for a new PC build, I don't have a CPU for it yet. I don't know what BIOS version it has and so don't know what is the newest CPU it will support. Is it possible to check version/flash the BIOS with just a PSU connected? I could just go for a fairly old CPU to get the board working but then I would a waste of CPU as I would then want to get the fastest one after BIOS upgrade. Catch 22 situation.

Any help much appreciated, thanks. Steve