I’m seeking help with a modded BIOS for the ASUS Prime Z390-A motherboard to properly support an Intel CC150 CPU (OEM, similar to i9-9900 but locked). Here’s my situation:
Issue:
The CC150 (CPUID 906E0) worked on BIOS v2004, but newer BIOS versions (e.g., 2101) fail to boot (red CPU LED).
Downgrading to v2004 no longer works (ASUS seems to have altered the microcode in re-releases).
Request:
Could someone provide or create a modded BIOS with:
Microcode for 906E0/906EC (to bypass ASUS’s OEM checks).
Hi, I’m experiencing the same issue with the CC150 on the ASUS Prime Z390-A.
Whenever the system follows the BIOS Fast Boot path, the motherboard shows a red CPU LED, the screen stays black, and the machine completely hangs — I can’t even enter the BIOS.
However, if I clear the CMOS or disconnect power, then on the next boot the board goes into Safe Boot mode instead of Fast Boot, and in that case it starts up successfully.
But as soon as I reboot, it falls back into the endless loop again (red CPU LED → black screen → hang).
It really seems related to how the BIOS handles microcode initialization for the CC150.
Thank you for your input. While I agree that a damaged CPU is theoretically possible, the evidence suggests this is almost certainly a BIOS-level compatibility issue, not hardware failure. Here’s why:
1. Prior Functional State
The CC150 worked flawlessly on BIOS v2004 .
Issues began immediately after updating to BIOS 2101 (and persist even when reverting to newer “v2004” files from ASUS).
If the CPU were damaged, it would have failed suddenly during operation—not after a routine BIOS update.
2. ASUS’s History with OEM CPU Restrictions
Multiple users report similar issues with OEM CPUs (e.g., Xeon E-2100/CC150) on ASUS Z390 boards after BIOS updates:
Reddit threads
Win-Raid cases.
ASUS has silently added OEM checks in newer BIOS versions (e.g., blocking non-retail CPUs).
No matter which official ASUS BIOS I flash now (v2004, 2101, or older) – via SPI programmer or USB – the CPU fails to boot. All versions after the original v2004 (which worked) seem to block the CC150. I need a modded BIOS with the original microcode or patched checks.
Unfortunately, I never saved the original v2004 BIOS file that worked with my CC150. All official BIOS downloads from ASUS (including the re-uploaded v2004) now seem to have altered microcode that blocks this CPU.
If anyone has a backup of the original v2004 BIOS (before ASUS changed the microcode) and is able to upload the file, please share a download link. I can flash it via SPI programmer (CH341A).
Tested the CC150 on a different board (ASUS TUF B360-PLUS Gaming) to confirm the CPU was working.
Ruled out hardware faults on the Z390-A by testing with a known-good CPU (Pentium G5420). The same red CPU LED error persisted, even with the good CPU.
Performed a BIOS downgrade on the Z390-A to version 0905 using the G5420. This allowed the system to boot normally.
Updated the BIOS to the latest version (v2101) with the G5420 still installed, using ASUS EZ Flash.
Reinstalled the CC150. The system booted successfully with BIOS v2101.
Conclusion: The solution was to use a supported CPU to downgrade and then re-upgrade the BIOS, which somehow reset the microcode or compatibility checks. No BIOS modding or programmer was needed. This empirical method worked where a simple CMOS reset or reflash failed.
That’s a really detailed explanation of your issue, and it definitely helps others understand what you’ve already tried. It sounds like the microcode changes in the newer BIOS are the main blocker here. Hopefully someone with experience in modding ASUS BIOS files can step in and share a working build or at least guide you through patching the microcode properly. This is a tricky one, but your post lays out the situation clearly.
Hi Sergi0, thanks for sharing your method in detail — it’s really helpful!
I have a PRIME Z390-A with an Intel CC150. On ASUS’s official website I can only find these older BIOS versions: 1903, 1902, and 2004. I don’t see the 1905 version you mentioned.
In this case, which version would you recommend I downgrade to first before upgrading back to the latest (2101)?
Maybe he meant bios 0905, since he mentions using Pentium G5420, so he might use older bios before 1xxx, to trigger some of the updates internally i guess?
I also tried downgrading with a G5420 using the ASUS EZ Flash 3 utility. Unfortunately, it only allows me to go back as far as 1105 — when I select 1005 or 0905, it shows the error “selected file is not a proper BIOS”.
From 1105 I then upgraded again to 2101, but the issue still remains. So at least on my board, I cannot revert to 0905 directly with EZ Flash 3.
@Sergi0 — could you share how you managed to downgrade the Z390-A BIOS to version 0905? Did you use a specific method (e.g., USB BIOS Flashback, CH341A, or something else) to bypass the EZ Flash restriction? Thank you very much!
For me, it worked using EZ Flash with an old, low-capacity USB stick formatted as FAT32 - but you’re probably already doing that. I just checked my download history from the ASUS website, and I don’t have versions 1005 or 1105 saved, so that eliminates any potential confusion on my part. The only BIOS version I had saved was 0905, meaning I couldn’t have installed anything else.
I didn’t use a programmer for this step, but if you have access to one, try flashing 0905 with it.
Also, please check that your Intel ME (Management Engine) version is 12.0.81.1753v4. This might be relevant to the compatibility issue.
Here’s another empirical suggestion you could try:
Reinstall the G5420 CPU on the motherboard.
Flash the oldest BIOS version that EZ Flash will accept (for example, 1105 in your case).
Assemble a minimal but complete system (CPU, one RAM stick, GPU if needed, and a boot drive).
Perform a clean installation of an official Windows 10 on the drive.
Once in Windows, run all available updates for this motherboard from the ASUS website in this specific order:
Install the latest Chipset drivers.
Install the Intel Management Engine (ME) drivers/firmware.
Finally, use the ASUS EZ Flash utility within Windows (or the BIOS) to update to the latest BIOS version 2101.
After you have confirmed that all drivers and the BIOS are fully updated, shut down the system.
Only then, swap the G5420 processor with the CC150.
The idea behind this method is to create a fully updated and stable software environment (including ME firmware and chipset drivers) with the supported CPU before introducing the CC150. This might help the system initialize the CPU correctly.
It’s a bit of a long shot, but it’s another thing to test if you have the time and components.