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XP running on a 486 cpu


Dietmar

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Posted (edited)

@roytam1 Until now,all the 486 cpu's are treated as the Pentium Overdrive 486 Podp5v83.This makes the aktual Xp slow on the Amd processors.For to speed them up a lot,we need to build a real xp486.iso ,where the correct cpu is listened via Cpuid.For me this is hard work,because no Windbg during very first steps of Setup.May be,in this situation an emulation can help a lot,when this emulation can build a real amd486 cpu Dietmar Edit: A elegant solution for this would be,to use the Source for Xp Sp1, adding all 486 cpu's there and just compile a new setupldr.exe and *.bin

 

 

Edited by Dietmar
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On 4/28/2024 at 4:52 AM, Dietmar said:

The same happened when using a ready IDE install and can be overcome only with the nice  hack from @roytam1 against Bsod 0x0000005D,

Bug Check UNSUPPORTED_PROCESSOR.

setupldr will boot NTKRNLMP.EXE, so you may need to replace it with our modded one.

EDIT: modded NTDLL.DLL doesn't work with usetup and getting 0xC0000005. with unmodded NTDLL.DLL gets 0xC000001E as usual.

image.png?ex=66310e99&is=662fbd19&hm=d3f

Edited by roytam1
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Posted (edited)

@roytam1

Please describe more exact this Bsod.

I test all my modded files a lot and now no kind of such a Bsod happens to me.

Does it happen during Setup of XP, my modded setupldr.exe and setupldr.bin together with my modded ntdll.dll

Dietmar

Edited by Dietmar
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6 hours ago, Dietmar said:

@roytam1

Please describe more exact this Bsod.

I test all my modded files a lot and now no kind of such a Bsod happens to me.

Does it happen during Setup of XP, my modded setupldr.exe and setupldr.bin together with my modded ntdll.dll

Dietmar

your setupldr.bin patch doesn't help and I still have to patch 75 to EB in 0x23513, and replacing NTKRNLMP.EX_ with our hacked NTOSKRNL.EXE.

because you didn't replace system32\ntdll.dll, it tries to use cmpxchg8b in NTDLL.DLL and BSODs:

image.png?ex=66318117&is=66302f97&hm=be0

 

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Posted (edited)

@roytam1

The ntdll.dll is patched.

So I dont know, where this Bsod happens

Dietmar

EDIT: Ah, I see, there is a second ntdll.dll on the xp.iso, crazy;))..

Edited by Dietmar
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Oh I think I find my problem: I can't replace resources with resource hacker in patched NTDLL.DLL.

so maybe every language of NTDLL.DLL has to be done separately.

Edited by roytam1
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@roytam1

I replace the second ntdll.dll with my modded one but get the same reboot just at the end of the Setup process, before you have to hit F8.

Please, can you tell me, what simulator you use for the AMD 486 cpu.

And is there a possibility, even in this very first Setup of XP to let Windbg watch it, may be via a crash debug log

Dietmar

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find the root of problem when changing NTDLL.DLL size.

@Dietmar you forgot to kill .rsrc section before adding your new section. (and add back .rsrc after filling new section, by using resource hacker)

had a hard time when relocating all related calls to new section. please keep in mind that variable size sections (for example, .rsrc) should be in last in the section list.

finally fixed NTDLL.DLL for localizations. fixed ger NTDLL: https://rthost.win/tmp/NTDLL-xpsp3-486hack-ger.7z

I can upgrade from 2000 to XP directly on 486 now:

image.png?ex=66326813&is=66311693&hm=a89

Edited by roytam1
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Posted (edited)

@roytam1

I am just testing on Shuttle Hot 433 board with AMD 133 MHZ486 cpu

AMD AM5x86-P75

Dietmar

EDIT: On real 486 compi, the same reboot happens before the F8 appears.

Is there something other, that you change on my "Source" CD for setup of german XP SP3 with all those modded files?

Edited by Dietmar
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Posted (edited)

Yessssaaa, it installs XP SP3 on my AMD 486 133MHZ cpu:cheerleader::cheerleader::cheerleader:  !!!!!!!!!!!!!!!!!!!!!!!!!

Even I do not get any Bsod before, I did exact the same extras as you:

Extra setupldr.bin patch 75 to EB in 0x23513 (strange, because it has CPUID), and replacing NTKRNLMP.EXE with our hacked NTOSKRNL.EXE,

niccccccccccccccccccccceee.. And I also delete logagent.exe and wmnetmgr.dll from the XP SP3 install CD,

because those 2 are the only files left, with CMPXCHG8b opcode in it

Dietmar

Here is the full fun

https://ufile.io/kresk3y1

Edited by Dietmar
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5 hours ago, Dietmar said:

@roytam1

I am just testing on Shuttle Hot 433 board with AMD 133 MHZ486 cpu

AMD AM5x86-P75

Dietmar

EDIT: On real 486 compi, the same reboot happens before the F8 appears.

Is there something other, that you change on my "Source" CD for setup of german XP SP3 with all those modded files?

Replacing resources with English one and repack it with cabarc.exe and replace same files in English CD.

WINNT32A.DLL and WINNT32U.DLL has CPU check cracked to allow 486 to run.

and English SETUPLDR.BIN has different offsets and I have to patch it manually (just patched the condition branch ops).

after 1st copying it reboots and got BSOD:

image.png?ex=66328080&is=66312f00&hm=ee5

Edited by roytam1
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@roytam1

With my XP TXTSETUP runs ok.

But then, after first reboot, compi hangs after about 4 min.

Sometimes hanging after about 4 min and sometimes during detect of devices (37min to wait is shown).

Are WINNT32A.DLL and WINNT32U.DLL on the german CD the same as on English ones?

Please tell me the crack or send me the already modded files

Dietmar

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