UEFI:NTFS - Boot NTFS partitions from EFI

This generic bootloader, which is primarily intended for use with Rufus, is meant to allow seamless booting from an EFI bootloader, that resides on an NTFS partitions. In other words, UEFI:NTFS is designed to remove the UEFI restriction of being able to natively boot from FAT32 only, and allow NTFS boot without the need for any user intervention.

This can be used, for instance, for booting an USB Windows NTFS installation media, in EFI mode, allowing support for files that are larger than 4GB (something a native EFI FAT32 partition cannot support), or allow indiscriminate EFI or BIOS boot of Windows To Go drives.

The way this works, in conjunction with Rufus, is as follows:

• Rufus creates 2 partitions on the target USB disk (these can be MBR or GPT partitions). The first one is an NTFS partition occupying almost all the drive, that contains the Windows files (for Windows To Go, or for regular installation), and the second is a very small FAT partition, located at the very end, that contains an NTFS EFI driver (see http://efi.akeo.ie) as well as the UEFI:NTFS bootloader.
• When the USB drive boots in EFI mode, the first NTFS partition gets ignored by the EFI firmware and the UEFI:NTFS bootloader from the bootable FAT partition is executed.
• UEFI:NTFS then loads the relevant NTFS EFI driver, locates the existing NTFS partition on the same media, and executes the /efi/boot/bootx64.efi or /efi/boot/bootia32.efi that resides there. This achieves the exact same outcome as if the EFI firmware had native NTFS support and could boot straight from NTFS.

Prerequisites

• Visual Studio 2015 or MinGW/MinGW64 (preferbaly installed using msys2)
• QEMU
• git
• wget, unzip, if not using Visual Studio

Sub-Module initialization

For convenience, the project relies on the gnu-efi library (but not on the gnu-efi compiler itself), so you need to initialize the git submodules:

git submodule init
git submodule update

Compilation and testing

If using Visual Studio, just press F5 to have the application compiled and launched in the QEMU emulator.

If using MinGW, issue: make TARGET=<arch> where <arch> is one of ia32 or x64. You can also debug through QEMU with MinGW by adding qemu to your make invocation. Be mindful however that this turns the special _DEBUG mode on, and you should run make without invoking qemu to produce proper release binaries.

Download and installation

You can find a ready-to-use FAT partition image (256KB), containing both the 32 and 64 bit versions of the UEFI:NTFS loader and driver in the Rufus project, under /res/uefi.

If you create a 256KB partition at the end of your drive and copy uefi-ntfs.img there (in DD mode of course), then you should have everything you need to make the first NTFS partition on that drive UEFI bootable.