[Success] Above 4G Decoding and Resizable Bar BIOS mod for ASUS P8Z77-V PRO


After removing 2nd, not RBAR capable GraphicsCard Windows does boot, but without display. And when turning off
after switching Show Fullscreen Post on Start-Up, the Windows Logo is not running at full resolution. Still UEFI Boot is on…

any further advice how to enable GOP or even unlock MSI BIOS?

Since this is Asus, is there any way OP can care to share how they unlocked 4g Decoding in the Z77 bios? It could shed a lot of light for the later gen boards of which I have tons from Z77 to Z97

The only issue is that the extracted files never have Above 4G or Decod in any string from the extracted text file - The only method I can figure is using the boot64efi port over.

Anyone have an idea on how to boot up the custom EFI USB and plug in the 4g decoding hex values/binaries without knowing exactly where they are? I’ve seen some bloke manage to do so on a dell motherboard with errors, but had it work correctly in the end anyways.

The DXE already is inserted, so I’m just trying to figure how to do this one.

If anyone can lay out clear and concise steps it would be awesome on how to get 4g decoding onto asus boards.

is there any way OP can care to share how they unlocked 4g Decoding in the Z77

the same method as described here Enabling hidden 4G decoding · xCuri0/ReBarUEFI Wiki · GitHub

Both 4g Decod and Above 4G are missing from the extract converted text document…

Any pointers if that’s the case? Someone had success banging in arbitrary values in a Dell Alienware - maybe I should follow them suit?

Apart from that, I’m having trouble booting the grub efi thing from a Windows 11 installer drive where I’ve thrown the grub thing into the efi boot directory.

Any clarifications would be awesome.

Motherboard is a Z87m Plus from Asus

You have the option available on the latest bios

Now, theres other strings present in bios but not visible, it may be needed to mod or not:

Good luck.

@MeatWar Memory Remap and Above 4G Decoding are not the same thing. And Memory Remap is anyways enabled by default.


Thank you m8, i just open the latest bios and made a search and shared the info, thats it, this is your work and project and you’re the guru on the user directions to follow, not me, cheers.

If you can figure out how to disable CSM by default (using AMIBCP) I can try and make a patch + DSDT edit for it to always enable 4G decode

Upload the latest version of your BIOS, and I’ll have a look. :slight_smile:

dont forget to update bios rx570 to support UEFI to fully support Resize Bar Feature, because while Resize Bar on CSM is auto disabled

, my rx 580 not boot correctly while CSM disabled in bios even using H610 (alder lake) board until i patching my rx 580 bios to support GOP+UEFI

Sounds simple enough right? Disable CSM by default, right? right?? snake? snaaaake!!!

I will have a look. Currently my bios is already set to UEFI and that’s what I cloned off the 64 flash chip and dumped it onto a new 128 winbond. I’ve already got the resize DXE installed, so I guess I can crack at this next part. If there are any alternate ways to enable 4g decoding, I am willing to pursue such avenues.

cheers, winkli


I found this. Some bloke was hammering generic hexes until 4g appeared to enable.

I also found the pinouts for the Nuvoton Superio’s which a lot of boards that do no have TPM headers have, which should technically allow for the installation of a TPM should one directly solder wires to the Superio - of course, requiring some super fine skills to do so.

I wonder if the DEBUG or COM ports have any of those prepared, so I can hook TPM up to some ancient asrock X79 boards, or even Z68, Z77, etc etc

I think I figured it out, I managed to disable CSM by default and enable 4g decoding on default through AMIBCP 4.55 for an X79 motherboard - which should be a similar idea to Z87.

The reason why it doesn’t work sometimes is because simply there are more than one instance of the setting enabled or disabled, so all of them need to be set to default and failsafe for it to work - Usermode for all menus and submenus that contain it seems to help it show up, too.

so in your Z87 there is no string for above 4g and csm toggle, but could you manage how to find/enable the above 4G and force it to CSM Off if there is no such option through amibcp?

Please read above, X79 is the motherboard that I managed to verify it on, an Asrock X79 Extreme 6 Motherboard

Also got it working for all of 1 reboot on windows 11 with a 9980HK on a Maximus VIII Hero. I remember reading about deleting a DXE to make space for the driver – or perhaps put it at the front of the DXE stack?

I’m working on the Z87 bios tonight

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Interesting, I can find “Above 4G Decoding” string to token ‘0x0F97’ in the bios file with AMIBCP v4.53.
But it is unable to find this string in the “Setup Configuation”, it’s even not a hidden option.

this is ASUS B85-Plus 2305 bios inserted with “NvmExpressDxe_5.ffs” and “ReBarDxe.ffs”, but when i’m trying to patch the DSDT follow the wikis, it is totally different, there is no CreateQWordField in my “DSDT.dsl”, is there anybody interested in it or you can help with it? thanks :joy:
B85PLUSNVME_Bar.rar (6.5 MB)

Check everywhere, but Asus probably never even inserted it into the bios in the first place :confused:

Got this now, the bios with the DXE installed and the CSM modes disabled? I think I pretty much covered all CSM mode settings.


Keep us updated, and thanks for helping hack it in :slight_smile:

One more thing, is there any way to inject TPM 2.0 compatibility instead of 1.2 only? I have some files dug out from an X99 Bios from Gigabyte’s SLI motherboard, which has TPM 2 code, but not sure if you can just drag and drop the corresponding 4 or so files – or if there’s anything else needed

@Wingklip I’m also interested in the TPM 2.0 mod so I can upgrade to Windows 11 and be able to play Valorant (requires TPM 2.0 on 11).

I wrote some of my findings here [Discussion] TPM 2.0 on unsupported motherboards

It requires DSDT modification in addition to DXE (especially the TPM SMI handler) and maybe PEI modules swap/add