Does AsRock block kaby lake bios downgrades?

Kyuunex wrote: I found z170m-ITX/ac for cheap. It will most likely come with a latest bios to support Kaby Lake CPUs. However, I wanna downgrade the bios so i can try that i5-6400 BCLK overclocking that apparently older bios version support or something. Many motherboard manufacturers block BIOS downgrades from Kaby Lake BIOS. Does asrock also do that? It's not stated anywhere in the BIOS download page. I just wanna make sure. Oh, and I accept all the risks involving overclocking.

I have never encountered the blocking of a UEFI/BIOS update to an earlier version, in any ASRock board. No one has ever reported having that happen to them, or asked about it in the forum.

I understand what you want to do, and I know you think it might have the 7.00 UEFI version for Kaby Lake support. But there might be another problem with your goal of trying BCLK over clocking.

I imagine you know Intel forced ASRock to kill the BCLK over clocking feature. The way that is done is with a UEFI/BIOS version that updates the CPU microcode that is part of the UEFI file itself. That CPU microcode prevents the BCLK OC from working. The UEFI version that has this CPU microcode is 2.20, given the descriptions for the UEFI versions. UEFI versions after that version will also update the CPU microcode, otherwise a user could skip 2.20, and still have the BCLK OC feature.

The problem is that not all earlier UEFI versions update the CPU microcode, versions 1.40, 1.60, and 1.70 do not update the CPU microcode. So installing one of those versions will not give you the BCLK OC feature.

What you will need to do, is to update to an earlier version that does update the CPU microcode, such as version 1.30. You may be able to just update to version 2.00 to get BCLK OC working. Just be sure you use a version before 2.20 that has a CPU microcode update.

Does this make sense to you?