This guide likely applies to other models and, potentially, even laptops from other OEMs that have NVME drives. However, I've only tested this on my Dell XPS 15 (9560) with the OEM Windows installation from the Signature Edition model.
Switching from RAID to AHCI is significantly simpler than switching from AHCI to RAID. All that's needed is a successful boot to Safe Mode.
-
To set the default boot mode to Safe Mode, use
msconfig.exe
or open an admin cmd/PowerShell window and run:bcdedit /set '{current}' safeboot minimal
-
Reboot and hit F2 to enter the BIOS.
-
Change the SATA mode to AHCI.
-
Save and reboot.
-
After Windows successfully boots into Safe Mode, disable Safe Mode with
msconfig.exe
or open an admin cmd/PowerShell window and run:bcdedit /deletevalue '{current}' safeboot
-
Reboot one last time. If you open the Device Manager, there should now be a
Standard NVM Express Controller
device under Storage Controllers.
Switching from AHCI to RAID is complicated and involves fiddling with the registry so that the RAID controller exists in the PnP database. Make sure you have a backup of your installation before proceeding.
NOTE: I've tested this under the OEM Windows 10 installation only.
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Before starting, ensure that the Intel RST drivers from the Dell support page are installed.
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Download DevManView and extract the ZIP file. This will be used to find the registry keys for the RAID controller because Device Manager is not available in the Recovery/WinPE environment.
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Hold down shift and click the Reboot button in the start menu. This will bring up the Advanced Startup menu on the next boot.
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Hit F2 to enter the BIOS when the system reboots.
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Change the SATA mode to RAID.
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Save and reboot.
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When the Advanced Startup menu appears, select the Command Prompt. It may ask for a login.
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The Recovery/WinPE environment contains its own copy of the Intel RST drivers so it is possible to access the Windows installation in RAID mode. Run DevManView from the Command Prompt to get a list of all the devices. For example:
C:\Users\chenxiaolong\Downloads\devmanview-x64\DevManView.exe
-
Hit Ctrl + F and search for
RAID
. There should be a device namedIntel Chipset SATA RAID Controller
. -
Right click the device and click
Open in RegEdit
. It should openregedit.exe
and nagivate to a path similar to the following:HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Enum\PCI\VEN_8086&DEV_282A&SUBSYS_07BE1028&REV_31\3&11583659&0&B8
-
Open
notepad.exe
in the Command Prompt and copy/paste the value ofClassGUID
from the registry. It will be needed later. In my case, the GUID was:{4d36e97b-e325-11ce-bfc1-08002be10318}
-
Right click the key in the treeview and export it to a file named
intel_raid_pnp.reg
. -
Navigate to
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Class\@ClassGUID@\0000
where@ClassGUID@
is theClassGUID
value obtained in step 11. -
Right click the key in the treeview and export it to a file named
intel_raid_class.reg
. -
At this point, we have all the registry keys, taken from the Recovery environment, almost ready to be applied to the Windows installation. There are just a few changes that need to be made because the
.inf
file referenced may not match what's in the Windows installation. -
Load the
SYSTEM
registry hive from the Windows installation. In the treeview, click onHKEY_LOCAL_MACHINE
and selectFile -> Load Hive...
. -
Select
C:\Windows\system32\config\system
and name the keyINTEL_RAID_FIX
. -
Nagivate to
HKEY_LOCAL_MACHINE\SYSTEM\DriverDatabase\DriverPackages
, find the key that begins withiastorac.inf_
, and make a note of the(Default)
value. This is the.inf
file for the Intel RST driver in the Recovery environment. In my case, this wasoem21.inf
. -
Nagivate to
HKEY_LOCAL_MACHINE\INTEL_RAID_FIX\DriverDatabase\DriverPackages
, find the key that begins withiastorac.inf_
, and make a note of the(Default)
value. This is the.inf
file for the Intel RST driver on the Windows installation. In my case, this wasoem44.inf
. -
Open both of the exported
.reg
files (intel_raid_pnp.reg
andintel_raid_class.reg
) and find and replace every instance of the following strings in both files:
\SYSTEM\
->\INTEL_RAID_FIX\
- Value from step 18 -> Value from step 19 (eg.
oem21.inf
->oem44.inf
in my case)
-
Save and close the
.reg
files. -
The registry changes are now ready to be merged. In the
File -> Open
dialog of Notepad, right click each of the.reg
files and clickMerge
. -
Navigate to the paths in steps 10 and 13, but change the location in the address bar from
\SYSTEM\
to\INTEL_RAID_FIX\
. Verify that the correct.inf
file is being referenced in the values. If the values are incorrect, please follow the instructions carefully, starting from step 10 again. -
Navigate to
HKEY_LOCAL_MACHINE\INTEL_RAID_FIX
and selectFile -> Unload Hive...
. -
Set the default boot mode to Safe Mode by running the following command:
bcdedit /set '{default}' safeboot minimal
-
Close all of the windows and reboot. With any luck, Windows will successfully boot into Safe Mode.
-
After Windows successfully boots into Safe Mode, disable Safe Mode with
msconfig.exe
or open an admin cmd/PowerShell window and run:bcdedit /deletevalue '{current}' safeboot
-
Reboot one last time. If you open the Device Manager, there should now be an
Intel Chipset SATA RAID Controller
device under Storage Controllers. -
It may be worth reinstalling/updating Intel RST from the Dell support page to ensure that everything is in a consistent state.
Thanks! This worked on my Dell XPS 15 9570 using the packaged Windows 10 install.