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Posted

Hi,

I noticed, that on all boards for the Arrow Lake cpu from Intel, there is no CSM for legacy boot of XP, Win7 etc. anymore in Bios.

About Quibble I heard, that it cant boot UEFI class 3 boards, which means no CSM at all.

So, only way is to do it by myself.

 

May be, that there is already a generic CSM dxe driver on the market, as the nvme.dxe from the Bios of the Samsung 850 for nvme boot.

 

I have a board gigabyte b760 ds3h ddr4. This has CSM. I use Bios F11 for it.

And I have a board for the Arrow Lake cpus gigabyte b860 ds3h, no CSM at all. I use Bios f6c for it.

 

My first try is  just to integrate those 3 CSM files from the F11 Bios into the f6c Bios.

CsmDxe.ffs

CsmVideo.ffs

CsmBlockIo.ffs

As I learned the hard way from the Asrock N100DC-ITX board, those drivers have to be enabled in Bios also.

 

This may be a much too naive try, because I heard, that CSM is deeply integrated in Setup in Bios.

Very small information you get about the definition of the integration of CSM in Bios. It is an UEFI dxe driver.

@Mov AX, 0xDEAD told me some times ago, that all the documents for CSM are Open Source,

but I have no idea, where to look for

Dietmar

 

 

 

 

 

 


Posted

@reboot12

Hi Gelip,

here is my first try.

The Bios from Gigabyte for both boards are VERY similar.

I put those 3 CSM files via UefiTool exact at those places where they where before in Bios F11.

Please take a look at the modded Bios, which Bytes needs to be set for to enable CSM.

Also I think, that Secure Boot has to be disabled.

Thanks a lot

Dietmar

 

Bios for the gigabyte b860 ds3h original and mod for CSM

https://ufile.io/ognrb00n

 

Posted

@reboot12

I succeed to flash my modded Bios via Q-Flash.

For this I just renamed my modded Bios to

GIGABYTE.BIN

and flash it with only Power Supply on, pressing the Q-Flash button.

Lasts about 3 min.

Oh,..soso much worry, but compi starts again ;)).

Of course no switch for CSM in Boot menu, but I think I can handle this like on the N100, if there is any chance

Dietmar

Posted (edited)

@reboot12

The Bios is NOT write protected, take a look at this

AmiSetupWriter.efi 0xd25 0x2

NVRAM variable "Setup" read, data size 0x1270, attributes 0x7.

Current Setup[0xD25] is 0x0

NVRAM variable "Setup" written.

Updated Setup[0xD25] is 0x2

Dietmar

EDIT: I just check with RU.efi, that indeed in UEFI name Setup now at adress 0xD25 is written 02.

But still no harddisk with MBR is recogniced.

Any idea, at which place I have to look for to enable CSM?

The dump of all adresses with names via AmiSetupWriter.efi -d > all.txt

does not work.

EDIT2: I also wrote for to enable CSM

AmiSetupWriter 0xCBE 0x1

The value at 0xCBE changed from 00 => 01

but still CSM is not working.

EDIT3: May be, that a compare of the Bios, from where this 3 csm files are taken, can help to set all (in Bios unseen) variables in the Bios above, its NVRAM for CSM boot, correct.

 

EDIT4: After checking about the risk, low, I did the following:

I replace via UEFITool the whole Setup Guide 899407D7-99FE-43D8-9A21-79EC328CAC21

in the Bios from the 245k with the one from the board with 12900ks cpu.

Before, I make a direct copy of the 12900ks Bios, fo to keep the settings for CSM.

Q-Flash allows this crazy Bios implantat.

But after reboot, I see only the screen, where I can choose between Delete (Bios Setup) or F12 (Boot menu).

No other reaction. I also clear CMOS, does not help. Compi is frozen at this screen.

But maybe this idea is not so bad, just you have to know, which parts of this Setup Guide have to be copied and which not.

Just now I flash the original Bios f6c back to the 245k board, compi is alive;))..

Edited by Dietmar
Posted
11 hours ago, Dietmar said:

My first try is  just to integrate those 3 CSM files from the F11 Bios into the f6c Bios.

CsmDxe.ffs

CsmVideo.ffs

CsmBlockIo.ffs

I do not think to insert only these 3 modules to get Legacy BIOS. Legacy bios and Legacy OptionROM's e.g. video bios is in csmcore module:
csmcore-vbios.png

Posted

@reboot12

How can I extract this csmcore? I do not see it with UEFITool.

And I remember another part in the NVRAM:

There has been a switch from Windows 10 ==> Other OS

Dietmar

Posted

@reboot12

I heard about this tool UBU but never used and so I also dont know, how to handle it.

Do you have an UBU version for me, that works for the 12900k and also for Arrow Lake (245k) here,

Dietmar

Posted

@reboot12

I notice, that in the Arrow Lake Bios this files are also missed:

67820532-7613-4DD3-9ED7-3D9BE3A7DA63  Aint13

4DF53F89-D421-4F9D-8392-BE3BECC6288E AhciInt13Dxe

4C006CD9-19BA-4617-8483-609194A1ACFC  Usbint13

C9A6DE36-FDFF-4FAF-8343-85D9E3470F43 Nvmeint13

501F30E9-D14F-47DA-AE60-B101E4189D07 Ahciint13Smm

So, some work is waiting;))

Dietmar

 

Posted (edited)

@reboot12

I just check: Csmcore has Guide A062CF1F-8473-4AA3-8793-600BC4FFE9A8

This is the same Guide as for the Bios from the 12900ks CsmDxe

Dietmar

Found Option ROM VBIOS in GUID A062CF1F-8473-4AA3-8793-600BC4FFE9A8

Edited by Dietmar
Posted (edited)

@reboot12

Yepp, I get via UBU from the 12900k Bios csmcore.

It starts via Winhex with CSM.

Now I just look, if this is already in my file CsmDxe

Dietmar

EDIT: Also in the 245k Bios a csmcore was build via UBU. But this one starts with CSM..MZ  no VGA video there.

Edited by Dietmar
Posted

@reboot12

Here is the documentation of CSM from Intel.

https://ufile.io/s8t2t9hw

I wonder, why also an csmcore was build for the Arrow Lake Bios.

May be, that UBU does not correct identify everything about CSM.

For example, there is no GUIDE number in it.

I also try the MMtool. No csmcore is listened in both Bios

Dietmar

Posted

And there are more files needed for CSM (legacy boot),

for example

71ED12D1-250B-42FB-8C17-10DCFA771701 AmiLegacyInterrupt

Dietmar

 

Posted
6 hours ago, Dietmar said:

I wonder, why also an csmcore was build for the Arrow Lake Bios.

Because bios has two Legacy OptionROMs - Network Boot ROMs Intel & Realtek and these are stored in csmcore:
two-OROM.png

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