Damnation

@Dietmar Can you check if HWINFO32 spits out garbage BIOS data with the latest acpi.sys 7777? It might be just a windows 2000 specific issue, but would like to verify.

@Dibya This is the latest one I have, might be out of date though. https://easyupload.io/tlms4s

@Comos That registry fix applies to XP too.

@Tecchie Make sure to use the x64 acpi.sys, the x86 acpi.sys won't work on XP x64.

@Dietmar From what I've found on Gigabytes website. https://www.gigabyte.com/WebPage/917/amd600-bios.html On the Favorites (F11) page. AMD at least still has CSM. (It might only apply to 600 series and not 800 series chipsets though) edit: https://www.gigabyte.com/WebPage/1081/amd800-bios.html All good, CSM support still there on the Main Menu page.

@Dietmar Have you tried running XP on Arrow Lake?

Unless someone makes a kernelex for XP, it won't work.

@Dietmar @reboot12 Have either of you given quibble a go to see if it can boot XP32 in UEFI64? https://github.com/maharmstone/quibble

@MilkChan So everything worked fine up until the sound driver was installed?

@Dietmar A few edits had to be made. Used -DWIN2K_COMPAT_SLIST_USAGE=1 switch when compiling. Stubbed HeadlessDispatch. Had acpi driver do ExInterlockedCompareExchange64 internally. Commented out HaliIsVectorValid where present. Needed to pass procinit explicitly to HalAcpiMachineStateInit in NotifyHalWithMachineStates.

@Dietmar Hi Dietmar, I've ported acpi.sys 7777 to now work with windows 2000 - can you apply all the hacks that you've applied to the XP version to this one too? https://easyupload.io/0qm58b

@Dietmar Does this mean we now have a way to enable CSM on UEFI class 3 systems?

@UCyborg It's about fixing XP's acpi.sys driver to work with newer hardware.

@Dietmar The one I linked does, maybe try that?

@Dietmar Does IDE work at least?