[Offer] Unlocked Asus ROG Strix Z790-A Gaming WIFI D4 BIOS

BIOS/UEFI Modding Offers: Already modded special BIOSes
1

This process is pretty straightforward, but I want to clarify a few things first. The only modification made to this firmware package, which was directly downloaded from the Asus ROG website, is that I unlocked the advanced setup menu. In other words, I revealed the hidden options.

I carefully unlocked settings that I determined wouldn’t conflict with others, especially those that caused issues like a black screen after changing BIOS settings. Resetting the CMOS fixed those problems, but the settings you’re likely looking for aren’t the ones I left hidden. The hidden ones are related to PCI-Express clocks, voltage, and similar complex options, which aren’t usually beneficial for most users. I kept these locked because accessing certain advanced menus can cause the UEFI setup to freeze or break essential functions, like selecting a boot device.

I’ve double-checked the menus to ensure everything important is accessible and functional. All the settings such as…

CFG LOCK,
BIOS LOCK,
OVERCLOCK LOCK,

Shall we proceed? HOLD… No wait, proceeding… :slight_smile:

I’m here to share a modified UEFI firmware/BIOS for the ASUS ROG STRIX Z790-A GAMING WIFI D4 (Build 2503, Build 3001). This guide will walk you through the process step by step. Please ensure you follow the instructions closely for a successful flash.

Instructions:

  1. Prepare the USB Drive:

    • Format a USB drive to FAT32 with a single partition. Ensure there are no hidden EFI partitions or any other partitions on the drive.

  2. Copy the Files:

    • Copy the included ROM file, SZ790AD4.CAP, to the root directory of your USB drive.

  3. Locate the BIOS Flashback Port:

    • Power off your system completely. Locate the BIOS FLASHBACK USB port on the rear I/O panel, just below the FLASHBACK button. It should be clearly labeled and color-coded for easy identification.

  4. Initiate the BIOS Flashback:

    • Insert the USB drive into the BIOS FLASHBACK port.
    • Ensure your power supply is set to “on,” but your system remains powered off.
    • Press and hold the FLASHBACK button for approximately 3 seconds. A flashing light indicates that the process has begun. Your system may light up, especially around the CPU VRM heatsink.

  5. Wait for Completion:

    • The process can take between 1-8 minutes. During this time, do not unplug the power, press any buttons, or interfere in any way. Sit tight and let the firmware update complete.

  6. Finishing Touches:

    • Upon completion, the system may automatically power on, or the LED on the FLASHBACK button may turn off. If the system does not power on by itself, press the CMOS clear button above the FLASHBACK button.
    • Enter BIOS by pressing F7 or navigating to Advanced Mode.

Important Warnings:

  • Do not attempt this process during inclement weather, especially during lightning storms, as power outages can result in a bricked motherboard. If this happens, a CH341A programmer will be required to recover, and I will not render aid with this. However, tutorials are readily available online & here on this web forum.

This modified firmware should provide all options hackintoshers, modification junkies, and troubleshooting gurus need. If you encounter any issues or have questions, feel free to reach out in this thread. Good luck, and happy modding!

Best Regards,
-MKGEN-

Version 3001 (NEW):

Download from Google Drive

Virustotal report here

Version 2503 (OLD):

>>> MOD FIRMWARE LINK HERE <<<

Edit by Fernando: Thread title specified and customized

3 Likes
2

Thank you for sharing with us.

1 Like
3

Could you share how you unlocked these hidden options? A lot of the guides are out of date now and I’d like to do this to my own bios files.

1 Like
4
1 Like
5

Hey man. Question to you.
I got the Z790-A Gaming Wifi, but without D4, basically the DDR5 equivalent.
Can you make such an mod bios too?
Do also think it would be possible to switch out the microcode?
Im planning on to use an intel core i5 12400F (if BCLK OC is doable), but this requires a different
MC for the processor in order to make the BCLK OC working. Some boards still show the BCLK
option, even with fixed MC, but you will see those capping out at around 103MHz.
Which is more or less normal.

1 Like
6

any chance you can unlock the latest bios 3001?

1 Like
7

Sure! Getting started on it right now. Check back in a few hours, should be up by then.

8

Yes, sorry, just saw this. Do you still need it for the none D4 version?

9

Okay! I’ll check back in a few hours!

10

As a curious request, I’m not quite sure what the limitations of editing BIOS are, but is there any way to allow for a lower BCLK (say 25MHz) and higher core, cache, and graphics ratios?

I know certain settings can be unhidden and have defaults changed, but I don’t know if limits are able to be changed. I also know that core ratios can be up to 120x in the standard BIOS.

In my particular case, I want to use a low BCLK (25 or 50 for example) paired with higher core ratios to achieve better granularity in adjustment of overclocks. I can do this to some extent currently with the stock BIOS, but the limitation is that the maximum iGPU ratio is 42x (2100MHz @ BCLK 100MHz), which would be an abysmal 840MHz at the standard minimum BCLK of 40MHz, and that wouldn’t be desirable for my use cases.

11

pieha,

Short version: with the modded Setup (we only changed the SuppressIf conditions and AccessLevel=05 to unhide the menus—no new options were invented), we can expose all the ratio/ICC knobs that Intel already baked into this platform. We cannot bypass fuse limits or add a brand-new BCLK domain that doesn’t exist in the PCH/FSP.

Details, tied to this exact board/CPU:

  1. BCLK at 25–50 MHz
  • Intel’s clocking on this platform uses fixed “straps” (100/125/167/250). 25/50 MHz are internal reference values for certain PLLs, not valid system BCLKs.
  • Dropping BCLK far below ~80–90 MHz destabilizes DMI/PCIe/SATA because they derive from the same clock tree. Even with ICC (Integrated Clock Controller) unlocked, ME will usually reject boots that far out of spec.
  • Conclusion: true 25–50 MHz system BCLK isn’t feasible here. The lowest practical range is roughly 80–90 MHz, and even that’s hit-or-miss.
  1. Core / Ring (Cache) ratios
  • Setup can now show very high ratio numbers (the UI goes to 120x), but the effective caps are enforced by CPU fuse/microcode (MSR 0xCE/0x194). On non-K parts you can’t exceed the fused max/turbo bins; the CPU ignores out-of-range requests.
  • Bottom line: we can expose and use the ratios, but we cannot raise maximum bins beyond what the silicon allows.
  1. iGPU (GT) ratio vs BCLK
  • On this CPU, the GT max ratio is fuse-limited (yours shows 42 → ~2.1 GHz at BCLK 100). When you lower BCLK, GT frequency scales down proportionally because the GT PLL follows the same reference.
  • Unless the CPU advertises “GT OC” via the OC mailbox (generally K-SKU behavior), raising GT ratio above the fused max is blocked. BIOS options can be unhidden, but the hardware limit still wins.
  • That’s why BCLK 40 MHz turns 42× into ~0.84–0.88 GHz—undesirably low—and there’s no safe way on this board/CPU to keep 2.1 GHz GT while running a 25–50 MHz system BCLK.

What we can do that actually works

  • Use the 100 MHz strap and rely on per-core and ring ratios for granularity (now unhidden), instead of dragging BCLK down into the danger zone.
  • If you need fractional headroom without hurting GT/DMI, use 125-strap and then fine-tune down a bit with ICC; this keeps the clock tree in a supported window while giving you smaller ratio steps.
  • If present in your CPU/FSP, we’ve also unhidden “GT Min/Max Ratio,” “GT Voltage,” and related GT controls. They’ll help stabilize at the fused limit, but they won’t lift the 42× ceiling.

Net answer to your question:

  • BIOS editing can unhide the relevant knobs and remove vendor-placed guards, but it cannot add a brand-new low-BCLK operating mode or bypass Intel’s fuse/microcode limits. On this motherboard/CPU, 25–50 MHz BCLK isn’t realistic, core/cache max ratios still respect fuses, and the iGPU’s 42× ceiling is hard-limited—so a low BCLK will inevitably drag GT frequency down unless you stay on a supported strap and tune with ratios/ICC instead.

I’ll be uploading the patched UEFI BIOS file with the unlocked values shortly, so you can flash it and explore the settings yourself. That’s my perspective on your question, though.

12

Thank you very much for your insight and detailed explanation! I’ll keep these in mind when I flash the patched BIOS.

1 Like
13

I’m making a few final adjustments. The previous version exposed too many unnecessary string entries, which only duplicated existing options and added clutter. These duplicates don’t affect UEFI configuration at all, but they slow down load times since more strings have to be generated.

For example, in the newly unlocked CPU CONFIGURATION section, the “string” subsections serve no purpose for configuration—they are purely descriptive. The only items that should have their accessLevel flipped (from 01, 29, or 09 to 05) are entries of type Numeric or OneOf.

Anyone modifying an ASUS ROG UEFI BIOS ROM should note: only Numeric and OneOf entries need to appear in the GUI, not strings.

Give me about 15 minutes to finalize and verify everything. Thanks for your patience.

1 Like
14

Version 3001, Z790-a strix WIFI-D4. Modified and unlocked GUI settings for hidden options.

or press here

15

I also work in cybersecurity, so as a matter of best practice I audit and analyze the files I download and modify. With that in mind, I verified both the original CAP file from ASUS as well as my modified version using VirusTotal. Both came back clean.

The one thing that initially raised concern was a “PEDLL” detection when VirusTotal unpacked the UEFI. In reality, this was a false identification: the file was flagged as a Windows DLL, when in fact it was a legitimate firmware module. This same signature appears consistently across all versions of the ROG Z790-A UEFI firmware, so it is not unique to my modified build. When scanned in the correct context as firmware, it shows zero detections. I also performed a deeper forensic audit, which confirmed that the image is clean.

This type of false positive is not unusual. A well-known example is how VirusTotal and ESET often flag official Dell BIOS files as UEFI malware because they include anti-theft tracking functionality. While technically accurate that these modules alter firmware behavior, they are in fact intentional and legitimate features, not malicious implants.

That little misstep is why this analysis took longer than expected. A brief scare, but ultimately nothing malicious at play.

Let me know if you have any further questions!

Keep the official version on an empty FAT formatted USB drive, with the .cap file directly in the root folder (if your USB drive is a D:\ drive, it would be D:\SZ790AD4.CAP) just in case you face an unexpected power outage or accidentally unplug the USB during flashing too early. It’s always good to have a known good image to revert to or upgrade to)

16

Looks great! Thank you very much for your help today! Have a great week!