ASUS P9D WS - Howto Disable PCIe to PCI Bridge via BIOS Mod?

BIOS/UEFI Modding BIOS Modding Guides and Problems
1

I’m attempting to disable the ASM1083/ASM1085 PCIe to PCI Bridge on my ASUS P9D WS Motherboard via BIOS Mod on a NAS System running Debian Linux. Yes, I know this is Win-Raid, but I think it’s one of the biggest BIOS Mod Community out there, so I hope that you can help me nevertheless.

This seems to be needed because in Linux the ASPM Support is disabled as soon as this Controller is detected.

@Darkestnoir did something similar in another Thread for another ASUS Motherboard → [Request] ASUS Prime B360M-C option to disable PCIe root ports

Following Step-by-Step the Instructions on GitHub - datasone/setup_var.efi: UEFI command-line tool for read/write access of variables, I exported the “Setup” String/Folder as Body from UEFITool.

However when attempting to open it using ifrextractor, I just get “No IFR data found”.

Did this occur to somebody else ? If so, how did you manage to get it fixed ?

Thank you for your Help :slight_smile:

Did you face a Similar Issue ?


Edit by Fernando: Thread title shortened

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image1285×687 31.5 KB

Section_Freeform_subtype_GUID_MiniSetupResourceSection_Setup_Setup_body IFR.zip (136.6 KB)

3

Thank you for your Reply. So it’s not the “Setup” that I need to export, just the “MiniSetupResourceSection” ?

4

It’s “something” “around there”

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image1356×866 75 KB

Right click - hex view: If there’s a lot of almost meaningful letters it’s worth a try.

5

Thank you.

Indeed it works if I select MiniSetupResourceSection (mostly HEX readable) instead of the “Top-Level” Setup (which has mostly HEX jibberish).

So I should be able to just set the Parameter using

setup_var.efi 0x96=0x0

Which should disable PCIe Root Port #2 to which the ASM1083/1085 is connected.

Only problem is that this Motherboard (ASUS P9D WS) apparently sucks big Time: UEFI support is completely broken. I cannot get Linux to UEFI boot (Hard Drive UEFI is NOT even detected in BIOS/UEFI), cannot get EFI Shell on a USB Stick to boot, cannot get Clover to UEFI boot either. All I see is a black Screen with a “_” (Cursor) at the Top. Nothing happens from there.

6

Can’t imagine that, owned a P9D-I and it had perfectly fine EFI support.

I’d assume other reasons, maybe a graphics card from that generation that has no EFI firmware?