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Windows 7 ISO as Bootable USB

How I solved the problem of making a bootable Windows 7 USB using readily available Linux tools

Although Windows 7 is long out of support, a friend asked me to assist in recovering his laptop OS, so I put aside my preferences and prejudices to see what I could do to help.

I found many sets of instructions about how to make a bootable USB after copying across the contents of the ISO. However, even the tools that were Linux based were not readily installed on a modern distribution.

I finally realised that Grub was all I required, and the following is a walk-through of the steps taken.

USB Drive Configuration

The drive needs to have sufficient capacity to hold the contents of the Windows 7 ISO (about 8 GiB).

Replace sdX below with the device associated with the USB drive.


The first step is to format the USB drive. The drive is formatted with an MSDOS partition table, with a single NTFS formatted partition. The label for the NTFS partition is W7SP1PRO64 (this will be used later).

Partition USB:

$ sudo sfdisk -d /dev/sdX <<EOF
label: dos

size=7.5GiB, type=7

Format partiton:

$ sudo mkfs.ntfs --fast -L W7SP1PRO64 /dev/sdX1

Copy ISO Content

Mount the ISO image to copy from (replace win7.iso with the name of your ISO file):

$ sudo mount -r -o X-mount.mkdir win7.iso /tmp/win7-iso

Mount the USB partition to copy to:

$ sudo mount -o X-mount.mkdir /dev/sdX1 /tmp/win7-usb

Copy ISO contents to USB:

$ sudo cp -v -r /tmp/win7-iso/* /tmp/win7-usb
$ sync

The sync may take a long time, dependent on the speed of your USB port and driver.

Make USB Bootable

Install Grub onto the USB drive:

sudo grub-install \
  --target=i386-pc \
  --install-modules="normal search ntfs ntldr" \
  --locales=uk \
  --boot-directory=/tmp/win7-usb \

Create the file /tmp/win7-usb/grub/grub.cfg (the label must match the label of the NTFS filesystem created above):

insmod ntfs
search --no-floppy --label W7SP1PRO64 --set root
ntldr /bootmgr


Unmount all of the drives, and arrange to boot from the USB drive. If all has gone well, you’ll see the Windows 7 installer.