Biostar B760MX2-E Pro D4 - unlocking ASPM options

BIOS/UEFI Modding BIOS Modding Guides and Problems
1

Hi all,

I am trying to mod the BIOS of this motherboard: Biostar B760MX2-E Pro D4 (https://www.biostar.com.tw/app/en/mb/introduction.php?S_ID=1127)

I want to enable ‘Native ASPM’ and other stuff to enable power management to get to deeper C-states (now I’m stuck in C3). These options are hidden for whatever reason. I want to unhide them.

Steps I tried:

  • Using setup_var.efi to write 0x1 to the ‘Native ASPM’ variable, but the BIOS is write-protected.
  • I extracted the AMITSE, setup, setupdata and opened the UEFI Editor tool. I removed the ‘Suppress If’ condition from ‘RC ACPI Settings’ and ‘Native ASPM’. I replaced the setup section with UEFI Tool. I tried flashing the modified image using the BIOS itself. It flashes successfully apparently but nothing changed in the BIOS. The option doesn’t become available.
  • Changing the default for ‘Native ASPM’ to 0x1 and resetting the BIOS to defaults. After doing this and reading the var with setup_var.efi still returns 0x2.
  • Because I thought the built-in BIOS flash procedure failed silently because of the modification, I read the ROM using a CH341A, modified that image and flashed it back. It went fine but I still didn’t notice any change in the BIOS after booting. So maybe the built-in flasher works but removing the ‘Suppress If’ isn’t enough?

Further investigation:

I noticed that the ‘Native ASPM’ is available in the BIOS in ‘Advanced - RC ACPI Settings - Native ASPM’. The ‘RC ACPI Settings’ item is suppressed with a condition.

0x3E415: 		SuppressIf  { 0A 82 }
0x3E417: 			EqIdVal QuestionId: 0x1253, Value: 0x0 { 12 06 53 12 00 00 }
0x3E41D: 			Ref Prompt: "RC ACPI Settings", Help: "System ACPI Parameters", QuestionFlags: 0x0, QuestionId: 0xA, VarStoreId: 0x0, VarStoreInfo: 0xFFFF, FormId: 0x271C { 0F 0F 4B 01 00 12 0A 00 00 00 FF FF 00 1C 27 }
0x3E42C: 		End  { 29 02 }

This question 0x1253 is also used in a lot of other suppressions:

  • Power & Performance
  • PCH-FW Configuration
  • Thermal Configuration
  • Platform Settings
  • ACPI D3Cold Settings
  • OverClocking Performance Menu
  • Debug Configuration
  • … and so on

This question doesn’t have a description:

0x76545: 			Numeric Prompt: "", Help: "", QuestionFlags: 0x0, QuestionId: 0x1253, VarStoreId: 0xF101, VarOffset: 0x139, Flags: 0x10, Size: 8, Min: 0x0, Max: 0xFF, Step: 0x0 { 07 91 00 00 00 00 53 12 01 F1 39 01 00 10 00 FF 00 }

Maybe it would be easier to just write 0x1 to the variable of this question (VarStoreId: 0xF101, VarOffset: 0x139) to unlock a bunch of settings? Although this could have other side effects.

Any advice to move forward with this is highly appreciated! I am not sure how to proceed.

Here you can find the latest BIOS image from Biostar (B76POA22.bss) and the extracted sections: https://www.dropbox.com/scl/fi/msmhm170zewqrhvtn5l8a/BIOS.zip?rlkey=jy5lbtx1vj5kkwrs0aqcgt9j2&st=5vhy4rki&dl=0

Thank you!!

Dean

2

could you try this, just replace the setup in original dump.

3

Hey Karfel,

‘RC ACPI Settings’ is available now, thanks so much! Would you mind explaining what you changed?

Edit: Okay I actually found out how to do it with some smart HEX editing. I now also unlocked some other menu’s so let’s see what we can get out of this hehe. Edit end

I enabled ‘Native ASPM’ but some devices still report that ASPM is not supported. Are there maybe some settings I am missing? I see there’s a bunch of others related to DMI ASPM.

00:1c.0 PCI bridge: Intel Corporation Device 7a39 (rev 11) (prog-if 00 [Normal decode])
                LnkCap: Port #2, Speed 8GT/s, Width x1, ASPM not supported
                LnkCtl: ASPM L1 Enabled; RCB 64 bytes, Disabled- CommClk+
00:1c.2 PCI bridge: Intel Corporation Raptor Point-S PCH - PCI Express Root Port 3 (rev 11) (prog-if 00 [Normal decode])
                LnkCap: Port #3, Speed 8GT/s, Width x1, ASPM not supported
                LnkCtl: ASPM L1 Enabled; RCB 64 bytes, Disabled- CommClk+

Could this be unlocked as well please, or I can try myself with a little explanation :slight_smile:

  • Chipset - PCH-IO Configuration - PCI Express Configuration - DMI Link ASPM Control
  • Chipset - System Agent (SA) Configuration (there are two?) - DMI/OPI Configuration
  • Package C State Limit option in CPU Power Management (it’s under Tweaker - CPU Power Management, but under Advanced - Power & Performance - CPU Power Management in UEFI Editor)

Thanks!

Dean

4

Good to hear that you figured it out on your own, lol. here for the explanation of what you just edited.