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[REQUEST] ASUS ROG STRIX B550-I GAMING BIOS Unlock
#1
I bought this board reading that bifurcation is possible, but turns out only x8x8 is available in the BIOS, whereas I need x8x4x4 for my riser.

Some boards have the PCI bifurcation setting in the PBS menu, but this one has very little there.

My understanding is this should be possible on this chipset/CPU - so hoping it can be unlocked in a modded BIOS.

Can anyone help with this please?

Support page: https://rog.asus.com/uk/motherboards/rog...l/helpdesk_bios
Latest BIOS: https://dlcdnets.asus.com/pub/ASUS/mb/So...G-ASUS-1803.ZIP

[Image: gEBWmIT.png]
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#2
I see two results for the string "x8x4x4" in UEFI tool. Extracting the PE32 file and extracting IFR, I see the same in both:

Code:
Form Sets -------------------------------------------------------------------------------- Offset: Title: -------------------------------------------------------------------------------- 0x5FA8 AMD PBS (0x2 from string package 0x0)



Within there, the match for "x8x4" is:

Code:
0x6124 Suppress If: {0A 82} 0x6126 Variable 0x2 equals value in list (0x1, 0x3, 0x4, 0x6) {14 8E 02 00 04 00 01 00 03 00 04 00 06 00} 0x6134 Not {17 02} 0x6136 End {29 02} 0x6138 Setting: PCIe/GFX Lanes Configuration, Variable: 0x11 {05 91 09 00 0A 00 08 00 01 00 11 00 10 10 00 03 00} 0x6149 Option: x16, Value: 0x0 (default) {09 07 0B 00 10 00 00} 0x6150 Option: x8x8, Value: 0x1 {09 07 0C 00 00 00 01} 0x6157 Option: x8x4x4, Value: 0x2 {09 07 0D 00 00 00 02} 0x615E Option: x4x4x4x4, Value: 0x3 {09 07 0E 00 00 00 03} 0x6165 End of Options {29 02} 0x6167 End If {29 02} 0x6169 Suppress If: {0A 82} 0x616B Variable 0x2 equals value in list (0x5) {14 88 02 00 01 00 05 00} 0x6173 Not {17 02} 0x6175 End {29 02} 0x6177 Setting: PCIe/GFX Lanes Configuration, Variable: 0x11 {05 91 09 00 0A 00 09 00 01 00 11 00 10 10 00 02 00} 0x6188 Option: x16, Value: 0x0 (default) {09 07 0B 00 10 00 00} 0x618F Option: x8x8, Value: 0x1 {09 07 0C 00 00 00 01} 0x6196 Option: x8x4x4, Value: 0x2 {09 07 0D 00 00 00 02} 0x619D End of Options {29 02} 0x619F End If {29 02}

Regardless of if I can enable the option, I've tried setting in EFI shell with:

Code:
setup_var 0x11 0x2

I see two errors doing this - Firstly the 'UEFI Interactive Shell v2.2' doesn't even seem to know that command, but instead 'setvar'.

Secondly, when I try with set var, it says "setvar: Unable to get - - 0x11"


I've seen guides on enabling the PBS menu itself ([OFFER] Gigabyte GA-AX370-Aorus Gaming 5 BIOS mod (12)), but not individual items within the menu.

In my case the BIOS already shows the PBS menu, but not these bifurcation options.
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#3
Sorry to keep rambling - but trying to solve my own question...

If I search instead for "Bandwidth Bifurcation" (the text in the menu option), I get a different sct and ifr file:

I don't really know why it's repeated three times:

Code:
Suppress If: {0A 82} 0x4A725 Variable 0x2E5 equals value in list (0x10, 0x40) {14 8A E5 02 02 00 10 00 40 00} 0x4A72F Variable 0x30C equals 0x0 {12 06 0C 03 00 00} 0x4A735 And {15 02} 0x4A737 Not {17 02} 0x4A739 End {29 02} 0x4A73B Setting: PCIEX16 Bandwidth Bifurcation Configuration, Variable: 0x184 {05 91 32 0E 33 0E 73 01 01 00 84 01 10 10 00 01 00} 0x4A74C Option: Auto Mode, Value: 0x0 (default) {09 07 3B 0E 10 00 00} 0x4A753 Option: PCIe RAID Mode, Value: 0x1 {09 07 3D 0E 00 00 01} 0x4A75A End of Options {29 02} 0x4A75C End If {29 02} 0x4A75E Suppress If: {0A 82} 0x4A760 Variable 0x2E5 equals value in list (0x2, 0x4, 0x80, 0x200) {14 8E E5 02 04 00 02 00 04 00 80 00 00 02} 0x4A76E Not {17 02} 0x4A770 End {29 02} 0x4A772 Setting: PCIEX16 Bandwidth Bifurcation Configuration, Variable: 0x185 {05 91 34 0E 35 0E 74 01 01 00 85 01 10 10 00 02 00} 0x4A783 Option: Auto Mode, Value: 0x0 (default) {09 07 3B 0E 10 00 00} 0x4A78A Suppress If: {0A 82} 0x4A78C 64 Bit Unsigned Int: 0x0 {45 8A 00 00 00 00 00 00 00 00} 0x4A796 64 Bit Unsigned Int: 0x1 {45 0A 01 00 00 00 00 00 00 00} 0x4A7A0 Equal {2F 02} 0x4A7A2 End {29 02} 0x4A7A4 Option: X8/X8 Mode, Value: 0x2 {09 07 3C 0E 00 00 02} 0x4A7AB End If {29 02} 0x4A7AD Suppress If: {0A 82} 0x4A7AF 64 Bit Unsigned Int: 0x1 {45 8A 01 00 00 00 00 00 00 00} 0x4A7B9 64 Bit Unsigned Int: 0x1 {45 0A 01 00 00 00 00 00 00 00} 0x4A7C3 Equal {2F 02} 0x4A7C5 End {29 02} 0x4A7C7 Option: PCIe RAID Mode, Value: 0x1 {09 07 3D 0E 00 00 01} 0x4A7CE End If {29 02} 0x4A7D0 End of Options {29 02} 0x4A7D2 End If {29 02} 0x4A7D4 Suppress If: {0A 82} 0x4A7D6 Variable 0x2E5 equals value in list (0x100, 0x400) {14 8A E5 02 02 00 00 01 00 04} 0x4A7E0 Not {17 02} 0x4A7E2 End {29 02} 0x4A7E4 Setting: PCIEX16 Bandwidth Bifurcation Configuration, Variable: 0x185 {05 91 34 0E 37 0E 75 01 01 00 85 01 10 10 00 02 00} 0x4A7F5 Option: Auto Mode, Value: 0x0 (default) {09 07 3B 0E 10 00 00} 0x4A7FC Suppress If: {0A 82} 0x4A7FE 64 Bit Unsigned Int: 0x0 {45 8A 00 00 00 00 00 00 00 00} 0x4A808 64 Bit Unsigned Int: 0x1 {45 0A 01 00 00 00 00 00 00 00} 0x4A812 Equal {2F 02} 0x4A814 End {29 02} 0x4A816 Option: X8/X8 Mode, Value: 0x2 {09 07 3C 0E 00 00 02} 0x4A81D End If {29 02} 0x4A81F Option: PCIe RAID Mode, Value: 0x1 {09 07 3D 0E 00 00 01} 0x4A826 End of Options {29 02} 0x4A828 End If {29 02}
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#4
Eventually I was able to run with this EFI Shell: https://github.com/tahmid-H/Asus-ROG-B55...n/EFI/BOOT

And then I could do:

Code:
setup_var AMD_PBS_SETUP 0x11 0x2

Unfortunately, it doesn't actually appear to work however.
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#5
You can try setup_var AMD_PBS_SETUP 0x11 again ,if its current value is 0x2 ,but the pci-e bifurcation is still not change to x8x4x4 ,it mean this feature is unavailable.

Or you could try ru.efi to edit it.

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#6
Thanks @genius239

>You can try setup_var AMD_PBS_SETUP 0x11 again

Do you mean just to *read* the variable, to make sure it's set? If so, the answer is yes. Even so, x8x4x4 doesn't seem to work.

> Or you could try ru.efi to edit it.

Is this for the case where the above didn't work to actually set the variable?

Do you know of any other way to enable, or is this likely this means the BIOS doesn't actually have the code to support it?
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#7
1. If you're sure the value was wrote correctly ,but the x8x4x4 mode didn't still active. It like you said, bios might not support this feature.

2. Now attempts setup_var AMD_PBS_SETUP 0x12 0x0 or setup_var AMD_PBS_SETUP 0x12 0x1 ,and test each of the result.

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#8
ah... I wondered why you suggested 0x12, but then I went and saw on the IFR there is another entry for this:

Code:
0x61A1 Suppress If: {0A 82} 0x61A3 Variable 0x2 equals 0x2 {12 86 02 00 02 00} 0x61A9 Not {17 02} 0x61AB End {29 02} 0x61AD Setting: PCIe/GFX lanes Configuration, Variable: 0x12 {05 91 0F 00 10 00 0A 00 01 00 12 00 10 10 00 01 00} 0x61BE Option: x8, Value: 0x0 (default) {09 07 11 00 10 00 00} 0x61C5 Option: x4x4, Value: 0x1 {09 07 12 00 00 00 01} 0x61CC End of Options {29 02} 0x61CE End If {29 02}

Did you just happen to guess that's there, or go and look it up yourself? In any case, thanks.

The trouble with that one is quite what x4x4 would even mean. I thought it had to be some split of x16.
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#9
See its help string then you will know.

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#10
Thanks for your help.

Do you mean help string "Setting: PCIe/GFX lanes Configuration, Variable"?

But that's the same as the previous 0x11 setting. Only the options here seem strange x4x4 doesn't add up to x16. Even with the help string, that doesn't make sense: Split this x16 into x4 and x4. That would be no good for me even if it made sense to throw away x8 of the lines.

But maybe I'm missing something.
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