Contents ----------- Introduction NT 5 - Install Win 8.1 - Dual Boot Win 10 - Install (1) Win 10 - Install (2) Win 10 - WIMBoot Win 11 - WIMBoot (1) Win 11 - WIMBoot (2) Win 11 - WIMBoot (3) Summary and notes GRUB4DOS --------------- GRUB4DOS - Device... GRUB4DOS - Fundamentals... GRUB4DOS - Command-Line GRUB4DOS - Install GRUB4EFI --------------- GRUB4EFI DiskPart ------------ DiskPart DiskPart - Command... DiskPart - USB... Misc. ----- WinPE USB... 64-bit Driver Signing NT 5 - TXTSETUP.OEM Add Hardware... UEFI, BIOS, GPT... UEFI Screen Res... Secureboot...

SVBus

Clone Windows 10 - WIMBoot

This page covers cloning an existing Windows 10 and setting up a dual boot Windows installation on UEFI or BIOS firmware. The instructions can be adapted to install Windows 8.1 update/10/11 (NOTE - previous versions of Windows do not support wimboot).

For more information about the Windows Image format - see here. Windows Image File Boot is covered here.

Setup\Requirements (see here).

Devices\Files\Paths (see here).

Step 1 - Setup a GRUB4DOS/GRUB4EFI bootable USB drive (see here).

Step 2 - Install SVBus (see here)

Step 3 - Turn off hibernate (see here)

Step 4 - Capture/clone Windows (see here).

Step 5a - Create and mount Virtual Hard Disk (see here).

Step 5b - Create and mount Virtual Hard Disk - low RAM systems (see here).

Step 6 - Copy wimboot .wim to VHD (see here)

Step 7a - Apply win10wimboot.wim to the mounted VHD (see here).

Step 7b - Apply win10wimboot.wim to the mounted VHD - low RAM systems (see here).

Step 8 - Create Boot Files (see here)

Step 9 - Registry Edits (see here)

Step 10 - Unmount Virtual Hard Disk (see here)

Step 11a - GRUB4DOS menu.lst (see here)

Step 11b - GRUB4EFI menu.lst (see here)

Step 12 - Boot Windows wimboot VHD (see here)

NOTE - Windows 8.1 Update or newer versions of Windows are required to complete Step 8. Previous versions of Windows do not include the Windows Overlay File System driver (wof.sys) and will not recognise the filesystem extracted in step 7. Windows 10 (1703) or newer is required to create and mount a multiple partition USB disk if a removable type disk is used.

Setup\Requirements

• Windows 10 Operating System - this system will be cloned.
• GRUB4DOS\GRUB4EFI bootable USB.
• GRUB4DOS for UEFI - version 2023-02-23 was used during testing. Download GRUB4DOS for UEFI from the http://grub4dos.chenall.net/categories/for-UEFI/ site.
• GRUB4DOS - version 0.4.6a 2020-03-04 was used during testing. Download GRUB4DOS from the http://grub4dos.chenall.net/ site -
• SVBus - available here. Version 1.3 was used during testing.
• wimlib - available here. wimlib is an open source alternate to DISM that can be used for some of the DISM commands including creating .wim files, extracting images, updating or deleting files, etc.

Devices\Files\Paths

The following table has been included as a reference to devices, files and paths that are used in the instructions in this page -

Step 1 - Setup a GRUB4EFI bootable USB drive

Create a bootable USB drive - this process is covered in more detail here. Include WinPE as this will be required in step 4 to capture/clone the Windows installation.

Step 2 - Install SVBus

In this step we will be installing SVBus to the live Windows system that will be cloned. Taking a backup of the Operating System is recommended before proceeding.

Run the following in an elevated cmd prompt (cmd.exe > run as administrator) -

D:\temp\SVBus\instx64.exe

You will be prompted to install the SVBus driver - select Install

Output -

SVBus Installer V1.3 Build 20221013 by Kai Schtrom OK : SVBus driver installed successfully

Step 3 - Turn off hibernate

The SVBus developer recommends disabling hibernation. In this step we will be disabling hibernation in the live Windows system before it is cloned. Taking a backup of the Operating System is recommended before preceding.

Open a command prompt (run as administrator) and execute the following command -

powercfg -h off

Step 4 - Capture/clone Windows

This step should be completed using WinPE - capturing the Windows system whilst it is offline. Boot the GRUB4DOS\GRUB4EFI bootable USB device.

Use the DiskPart list volume command to identify the drive letters for the Operating System to be cloned (C: in the example below) and the destination (D: in the example below)

If using DISM (note the use of the /WIMBoot parameter) -

DISM.exe /Capture-Image /ImageFile:D:\temp\win10wimboot.wim /CaptureDir:C: /Name:"Win10 SVBus cloned" /WIMBoot

Alternative using wimlib (note the use of the --wimboot parameter) -

wimlib-imagex capture C: D:\temp\win10wimboot.wim "Win10 SVBus cloned" --wimboot

On the test system (the ThinkPad T470s), the operating system being cloned contained Windows 10 21H2 with updates and Office 2016 installed. Disk usage prior to capture was 24 GB. win10wimboot.wim file size = 6.9 GB.

The remaining steps can be completed in WinPE. Alternatively, reboot to Windows 10 and complete the remaining steps in a full OS.

Step 5a - Create Virtual Hard Disk

Proceed to step 5b if following the instructions for use on low RAM systems.

A VHD with two partitions is used as this supports booting the same file on UEFI and BIOS firmware. The first partition (FAT32 file system) will be used for the boot files required to load the operating system located in the second partition when the VHD is mapped using GRUB4DOS/GRUB4EFI (see here for more information).

For the Windows 10 WIMBoot tests, the following DiskPart commands were used to create a 12GB virtual hard disk (change size, filename, path and mount point according to your own requirements) -

create vdisk file=D:\wimboot.vhd maximum=12288 type=fixed attach vdisk create partition primary size=100 format fs=fat32 label=vhdboot quick assign letter=V active create partition primary format fs=ntfs label=vhdos quick assign letter=W

Step 5b - Create Virtual Hard Disk - low RAM systems

Ignore this step if you followed step 5a.

On low RAM systems, win10wimboot.wim can be left in the path D:\temp\win10wimboot.wim rather than being copied to the mounted VHD file. This can significantly reduce RAM usage when mapping the VHD file as a RAM disk, as the VHD file only needs to be large enough for file dependencies that are extracted in full from win10wimboot.wim (in step 7b). Additional space is required for the systemdrive so that Windows will run, however the RAM requirement is effectively reduced by the file size of win10wimboot.wim.

For the Windows 10 WIMBoot tests, the following DiskPart commands were used to create a 5GB virtual hard disk (change size, filename, path and mount point according to your own requirements) -

create vdisk file=D:\wimboot.vhd maximum=5120 type=fixed attach vdisk create partition primary size=100 format fs=fat32 label=vhdboot quick assign letter=V active create partition primary format fs=ntfs label=vhdos quick assign letter=W

Step 6 - Copy wimboot .wim to VHD

Ignore this step if following the instructions in Steps 5b and 7b (low RAM systems)

Copy the wimboot .wim file to partition 2 in the mounted VHD file -

copy D:\temp\win10wimboot.wim W:\ /Z

Step 7a - Apply win10wimboot.wim to the mounted VHD

Proceed to step 7b if following the instructions for use on low RAM systems.

Extract the contents of image 1 in W:\win10wimboot.wim to the target drive (W:\ - partition 2 in the mounted .vhd file) - adjust paths as required. Note the use of the /WIMBoot parameter -

DISM.exe /Apply-Image /WIMBoot /ImageFile:W:\win10wimboot.wim /Index:1 /ApplyDir:W:\

Alternative using wimlib. Extract the contents of image 1 in W:\win10wimboot.wim to the target drive (W:\ - partition 2 in the mounted .vhd file) - adjust paths as required. Note the use of the --wimboot parameter -

wimlib-imagex.exe apply W:\win10wimboot.wim 1 W: --wimboot

Step 7b - Apply win10wimboot.wim to the mounted VHD - low RAM systems

Ignore this step if you followed step 7a.

On low RAM systems, win10wimboot.wim can be left in the path D:\temp\win10wimboot.wim rather than copied to the mounted VHD file. This will reduce RAM requirements by the file size of win10wimboot.wim when mapping the VHD file as a RAM disk.

Extract the contents of image 1 in D:\temp\win10wimboot.wim to the target drive (W:\ - partition 2 in the mounted .vhd file) - adjust paths as required. Note the use of the /WIMBoot parameter -

DISM.exe /Apply-Image /WIMBoot /ImageFile:D:\temp\win10wimboot.wim /Index:1 /ApplyDir:W:\

Alternative using wimlib. Extract the contents of image 1 in D:\temp\win10wimboot.wim to the target drive (W:\ - partition 2 in the mounted .vhd file) - adjust paths as required. Note the use of the --wimboot parameter -

wimlib-imagex.exe apply D:\temp\win10wimboot.wim 1 W: --wimboot

NOTE - do not move, rename or delete D:\temp\win10wimboot.wim if using this method.

Comparison between step 7a and step 7b - available disk space when Windows 10 is booted and running from a RAM disk -

1. Step 7a (wim in VHD)	2. Step 7b (wim on SSD)

Step 8 - Create Boot Files

Use the bcdboot command to create boot files in Drive V:\ (the first partition in the virtual hard disk. See here for more information about bcdboot usage).

bcdboot W:\windows /s V: /f ALL

Specifying the /f ALL parameters will create BIOS and UEFI boot files, facilitating the use of the VHD on BIOS or UEFI firmware.

Step 9 - Registry Edits

The following tasks will be completed in this step -
Mount registry > delete MountedDevices key > delete pagefile > disable Windows Update > unmount registry

reg.exe load HKLM\_SYSTEM W:\Windows\system32\config\system reg.exe load HKLM\_SOFTWARE W:\Windows\system32\config\software

Delete the HKLM\_SYSTEM MountedDevices key (this is the mounted W:\Windows\system32\config\system registry hive). Clearing the MountedDevices key will force the cloned Windows to reallocate drive letters - resulting in the cloned operating system being mounted as C: when booted.

reg delete "HKLM\_SYSTEM\MountedDevices" /va /f

Clear the existing pagefile settings (HKLM\_SYSTEM MountedDevices is the mounted W:\Windows\system32\config\system registry hive) -

reg add "HKLM\_SYSTEM\ControlSet001\Control\Session Manager\Memory Management" /v ExistingPageFiles /t REG_MULTI_SZ /d "" /f reg add "HKLM\_SYSTEM\ControlSet001\Control\Session Manager\Memory Management" /v PagingFiles /t REG_MULTI_SZ /d "" /f

Disable Windows Update. Recommended to avoid the free disk space being filled with updates.

reg add "HKLM\_SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU" /v NoAutoUpdate /t REG_DWORD /d 1

Unmount the registry hive -

reg.exe unload HKLM\_SYSTEM reg.exe unload HKLM\_SOFTWARE

Step 10 - Unmount Virtual Hard Disk

Enter the following DiskPart commands to detach/unmount the virtual hard disk -

select vdisk file=D:\wimboot.vhd detach vdisk

Step 11a - GRUB4DOS Menu.lst

Add the following entries to R:\menu.lst (if the instructions here were followed there should be an existing file with an entry for WinPE) -

title wimboot.vhd - SVBus RAMDISK find --set-root --ignore-floppies /wimboot.vhd map --top --mem /wimboot.vhd (hd0) map (hd0) (hd1) map --hook root (hd0,0) chainloader /bootmgr title wimboot.vhd - SVBus FILEDISK find --set-root --ignore-floppies /wimboot.vhd map /wimboot.vhd (hd0) map (hd0) (hd1) map --hook root (hd0,0) chainloader /bootmgr

Note the use of the map --top --mem command - see here for more information.

See here for more information about the configuration file \menu.lst, including potential issues with multiple configuration files on the same system.

Step 11b - GRUB4EFI Menu.lst

Add the following entries to R:\EFI\grub\menu.lst (if the instructions here were followed there should be an existing file with an entry for WinPE) -

title wimboot.vhd - SVBus RAMDISK find --set-root /wimboot.vhd map --mem --top /wimboot.vhd (hd) chainloader (hd-1) title wimboot.vhd - SVBus FILEDISK find --set-root /wimboot.vhd map /wimboot.vhd (hd) chainloader (hd-1)

Note the use of the map --top --mem command - see here for more information.

See here for more information about the configuration file \EFI\grub\menu.lst, including potential issues with multiple configuration files on the same system.

Step 12 - Boot Windows wimboot VHD

Following the installation, Windows can be booted by first booting GRUB4DOS\GRUB4EFI and then selecting either the wimboot.vhd - SVBus FILEDISK or wimboot.vhd - SVBus RAMDISK menu entries.

Screenshot of Windows running in a RAM disk - Step 7a followed with the wim backing file contained in the GRUB4DOS/GRUB4EFI mapped VHD (note the disk usage is 7.44 GB with win10wimboot.wim taking up 6.9 GB of the available space) -

Screenshot of Windows running in a RAM disk - Step 7b followed with the wim backing file running from the internal SSD rather then the VHD (note the disk usage - 537 MB) -

Document date - 12^th April 2023