After cloning and migrating my Windows XP install From an Old Asus MB to a New(ish) Gigabyte GA-P35C-DS3 Main board (read this first: xp clone & migrate (without install)), I experienced an issue whereas I've lost access to all my SATA HDDs.

What I eneded up with was a booting Windows XP OS from an IDE HDD, while all my other SATA II HDDs were missing.

In total I had 3 other SATA HDDs, connected to their respective SATA ports:

• 2 SATA WD Caviar RE2 500 GB.
• 1 SATA WD Raptor X 150 GB.

I used those disks for storage & backup purposes (& for Ubuntu of course [on the Raptor]).

I needed access to the  SATA HDDs from Windows XP, 'though:

1. My New Gigabyte MB's chipset was "Standard ICH9 (ie. non-RAID)". This is important due to Drivers'-related issues (see point No.4).
2. On my Old Asus MB BIOS, I did check (enable) "AHCI Mode" for SATA HDDs (that is because my Raptor supported NCQ).
3. On my Old Asus MB, I did install Windows XP to a SATA HDD in AHCI Mode.
4. Not intel nor Gigabyte does ship a "AHCI ICH9 XP driver" (shame on them!).

After searching up and down, I found a simple way to hack the official intel ICH9 Drivers and enable AHCI support for vanilla ICH9 Chipsets(!).

To apply this hack, proceed as follows:

• Get your Chipset Drivers from intel - What I got is "iata78_enu.exe", but I'm expecting other versions should work too.

Now launch a command shell and execute:

• iata78_enu.exe -a
• Follow the wizard as if you wanted to perform a normal install.
• Open Explorer.exe & browse to C:\ Program Files -> Intel -> Intel Matrix Storage Manager -> Driver [or Driver64 if using XP64].

You will find some .sys file within "C:\Program Files\Intel\Intel Matrix Storage Manager\Driver".

In order to apply the hack, now proceed as follows:

1. Copy/paste "IaStor.sys" to C:\Windows\System32\Drivers
2. Open "iaahci.inf" with notepad and CTRL+H (to Search and Replace).
3. Change "2821" to "2923" in all occurences.
4. CTRL+H again (to Search and Replace).
5. Search for this string: PCI\VEN_8086&DEV_2922&CC_0106.DeviceDesc = "Intel(R) ICH9 SATA AHCI Controller".
6. Change string at point No.5 to: PCI\VEN_8086&DEV_2923&CC_0106.DeviceDesc = "Intel(R) ICH9 SATA AHCI Controller".
7. Close and save.

The above steps modify the intel iaahci.inf file to tell Windows XP to recognise your Controller as AHCI-enabled controller.

Next you'll need to enable AHCI support on Windows XP.

to enable AHCI support on Windows XP, proceed as follows:

• Open Notepad to create a new file.
• Paste the following content to it:
• Windows Registry Editor Version 5.00 ; Der Treiber iaStor.sys muss vorher in das Verzeichnis ; Windows\system32\drivers\ kopiert werden ; Erstellt am 10.08.2007 von www.jzelectronic.de ; Für ICH9: www.intel.com ; Trademarks: Intel (www.intel.de), Microsoft (www.microsoft.de)[HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\CriticalDeviceDatabase\pci#ven_8086&dev_2923&cc_0106] "Service"="iaStor" "ClassGUID"="{4D36E96A-E325-11CE-BFC1-08002BE10318}"[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\iaStor] "Type"=dword:00000001 "Start"=dword:00000000 "Group"="SCSI miniport" "ErrorControl"=dword:00000001 "ImagePath"="system32\\drivers\\iaStor.sys" "tag"=dword:00000019 "DisplayName"="Intel AHCI Controller"[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\iaStor\Parameters] "queuePriorityEnable"=dword:00000000 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\iaStor\Enum] "0"="PCI\\VEN_8086&DEV_2923&SUBSYS_B0051458&REV_02\\3&13c0b0c5&0&FA" "Count"=dword:00000001 "NextInstance"=dword:00000001
• Save the new file as ahci.reg (make sure the new file doesn't get a txt extension appended to it).
• Execute ahci.reg and say yes when prompted.
• Reboot Windows.

Once Windows Restarts, you'll get prompted with the install hardware wizard for a misterious "PCI Device".

• Choose expert mode.
• Specify the path of the previous file, C:\Program Files\Intel\Intel Matrix Storage Manager\Driver\iastor.sys
• If it's all good, you'll be prompted to install an unsigned driver (blame intel for this hack).
• Once you do, your SATA HDDs should now start to popup and you will be able to access and use them normally.

Infos taken and freely re-elaborated with my experience from Gigabyte support forum: http://62.109.81.232/cgi-bin/sbb/sbb.cgi?&a=show&forum=1&show=3792&start= (German).

[UPDATE-2017-02-05]: Reviewed whole article - it didn't make any sense 🙂