NOTE - this guide has been updated to include information/instructions about the use of SVBus on systems with UEFI firmware, something now possible with the development of GRUB4DOS for UEFI and al1ve's fork of GRUB 2.

The SVBus driver has been developed by Kai Schtrom and is available here. Usage includes booting the following versions of Windows from a RAM Disk or a Virtual Disk -

The following versions of Windows Server have not been tested, but should also be supported -

SVBus is a virtual SCSI Driver for use with GRUB4DOS/GRUB4EFI [NOTE - GRUB4EFI is officially referred to as GRUB4DOS for UEFI]. SVBus can be used to access GRUB4DOS/GRUB4EFI mapped drives from Windows, which includes booting Windows from a virtual disk file or from RAM. This guide will focus on installing Windows to a Virtual Disk and subsequently booting Windows from either a virtual disk or a RAM disk -

Some versions of Windows already support booting from a Virtual Disk following the introduction of Native Boot VHD in Windows 7. VHD Boot is not supported in all editions of Windows, in Windows 7 for example it is limited to use on Enterprise and Ultimate editions of the Operating System. SVBus can be used as an alternative, however it does have some limitations -

This guide contains instructions for installing the following Windows Operating Systems on systems with BIOS firmware -

This guide has been updated with instructions for running Windows NT 10.* on systems with UEFI firmware.


Windows native tools have been used throughout this guide where possible, however the majority of these tools require Windows 7 or newer Operating Systems. The Windows Preinstallation Environment (WinPE) can be used as an alternative, and is available as a free download from Microsoft via the Windows Assement and Deployment Kit (see here). WinPE version 3 or newer is required.

Test systems

The following systems were used in the tests/walkthroughs in this guide -

Document date - 12th April 2023