I read the thread on downgrading the ME. The instructions are very vague. I guess they meant for someone who is more advanced and I’m new to this.

Thank you anyway for trying out the BIOS. It's good feedback, and I'm glad nothing is broken!

No prob. If I figure out how to downgrade the ME. I will report back

@thewkong - the instructions are very specific, so yes it must look vague to you because your not familiar with that kind of thing. A week or two ago I made a guide, in order to remove a similar lock, not the same, but similar guide to utilize the method you need for unlocking ME so you can flash to older ME.
Here is that guide, again this is not for this specific issue, but more to familiarize yourself with this process through a guided process with images, tools, and method shown on removing a similar lock - [GUIDE] Grub Setup_Var Guide - Fix Intel FPT Error 368 - BIOS Lock Bit Set HSFS W/ Asus or Other Mod BIOS

You've already tried to flash backwards using the FW update tool, correct and it failed? Have you researched and found the version of ME you want to use?
As mentioned, I think it does need to be 11.6.xx.xx but I am not sure if there is a specific best one or suggested one to use etc, assuming maybe you read around and found this info already.
If yes, please specify the ME, and I will put together a package for you and anyone else in this thread that needs it later. I'll show you exact ME FW update command to use, and or create BIOS from this BIOS in thread with the older ME, so you can then flash BIOS once ME Lock is removed.

To shorten the steps needed, I have looked in this BIOS already, and the setup_var variable you need to change is this (For this specific BIOS only) >> 0x3E
Change this variable from 0x1 to 0x0. This can be done following the guide I linked above, or I can create a BIOS for you with this already unlocked within it and including any specific ME you want and it will all get flashed at once when you reflash BIOS

And here is quick guide I made on how to do this mod to the BIOS itself (Enable ME Re-Flash), in spoiler at post 4068
Obviously this guide was meant for that specific BIOS, so do not use the values provided there, only follow method to find this boards values and change via hex
Intel Management Engine: Drivers, Firmware & System Tools (272)
If this method is used, you need to insert ME version you want into the BIOS too.

Wow. It worked!!! Lost N Bios you were absolutely correct. I was changing the variable 0x28 but I should have changed 0x3e from 0x1 to 0x0. I was able to downgrade the ME after that and I flashed my motherboard with the bios that ultimahwhat modded and it worked. My i3-8100 now works with my z170 fatal1ty itx board. Thank you guys because I wouldn't have been able to figure it out.

You're welcome, cool you were able to get it flashed without further hassles!

Zitat von thewkong im Beitrag #20

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Wow. It worked!!! Lost N Bios you were absolutely correct. I was changing the variable 0x28 but I should have changed 0x3e from 0x1 to 0x0. I was able to downgrade the ME after that and I flashed my motherboard with the bios that ultimahwhat modded and it worked. My i3-8100 now works with my z170 fatal1ty itx board. Thank you guys because I wouldn't have been able to figure it out.

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After the changing variable 0x3e, the Intel ME firmware was 0.0 and after installing the modded BIOS, the Intel firmware is 11.6. It was 11.8 before.

I’m not at home so I can’t check on what the whole firmware number is but it starts with 11.6.

Thanks. That's where my Intel firmware is, so that gives me hope that 6-core Coffee Lake might work on my board (4-core confirmed).

@thewkong the next million dollar question is how far you can increase BCLK on this board with a Coffee Lake CPU? The internet suggests there is a hard cap of 103.0 MHz on BCLK on Z370 boards, but maybe that doesn't exist with this board and the lower version of Intel ME?

That limit may lie in the ME itself, there is a few overclock profiles, and only certain amounts % allowed in each. That can be changed to a certain degree in some ME versions, less and less the newer the ME
This is set in the integrated clock controller section of the ME, there is several profiles to choose from (Include or not include) Standard, Adaptive, overclocking, overclockingplus, overclockingetx (Only adaptive and overclockextr on Z370 chipset selection)
None can be set to go above 100Mhz in 11.0 or 11.6 ME, even when bclkmaxfreq allows 170/341/538 in the overclocking profiles, remnants of when more was allowed in previous older ME or possibly left to be further enabled by BIOS with non-Intel clock generators
Now, this may not always apply to the BIOS, or what's been set/structured into the BIOS aside from ME, I'm only talking ME setting allowances here.

Zitat von Lost_N_BIOS im Beitrag #27

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That limit may lie in the ME itself, there is a few overclock profiles, and only certain amounts % allowed in each. That can be changed to a certain degree in some ME versions, less and less the newer the ME
This is set in the integrated clock controller section of the ME, there is several profiles to choose from (Include or not include) Standard, Adaptive, overclocking, overclockingplus, overclockingetx (Only adaptive and overclockextr on Z370 chipset selection)
None can be set to go above 100Mhz in 11.0 or 11.6 ME, even when bclkmaxfreq allows 170/341/538 in the overclocking profiles, remnants of when more was allowed in previous older ME or possibly left to be further enabled by BIOS with non-Intel clock generators
Now, this may not always apply to the BIOS, or what's been set/structured into the BIOS aside from ME, I'm only talking ME setting allowances here.

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Got a 2 core G4900 Coffee Lake to work on this board by following guides linked to this thread and creating a BIOS. Thanks for all the expert posts!

Glad to hear it, enjoy!