How to create a Windows 11 bootable USB drive using Ubuntu

I recently had to install Windows 11 on a FreeDOS machine, and I hit a lot a couple of walls in the process:

• My main problem was that I didn’t have access to another Windows machine to download the .exe files in the Windows 11 downloads page.
• The second issue was that the machine only accepted FAT32 devices to boot from, and the Windows 11 ISO contains a file larger than 4gb (the maximum allowed size for a file in the FAT32 file system).

So I decided to document what worked for me to overcome these issues.

Update 🤦‍♂️: It turned out that there was a much easier and straightforward way to solve the issue using macos.

1. Install Ubuntu

I only had access to a macos machine, these are the steps I followed:

• Download the Ubuntu ISO.
• Use the Balena Etcher software to burn the ISO into the USB drive.
  • Note: I tried to use the same software for burning the Windows 11 ISO, but that didn’t work due to the 4gb file size restriction.
• Boot Ubuntu on the FreeDOS machine using the USB drive, and install it.

2. Download the Windows 11 ISO

This is an easy step, just download the Windows 11 multi-edition ISO in your desired language.

3. Format the USB drive

• Connect the USB drive to the machine running Ubuntu.
• Open the Disks application.
• Select the USB drive.
• Tap on Format → Partition using MBR / DOS → Format.
• Create a partition → Select FAT type.

Note: This will delete all the files from the USB, so it’s ready for us to burn the Windows image.

4. Split the install.wim file

We need to split the install.wim file inside the Windows 11 ISO given it is larger than 4gb and exceeds the FAT32 file size limit.

• Mount the Windows 11 ISO in your Ubuntu machine.
  • Right click the ISO.
  • Open With → Disk Image Mounter.
• Open the mounted image in the file system.
  • Copy the install.wim file inside the sources folder to your Desktop.
• Install wimtools from the console.
  • sudo apt-get install wimtools.
• Split the install.wim file into smaller files.
  • wimlib-imagex split install.wim install.swm 4000.

5. Prepare the bootable USB

• Copy all the files from the mounted ISO image to the USB drive except for the install.wim file.
• Copy all the install.swm files generated before and paste them in the sources folder of your USB drive.

🎉 Now you have a bootable Windows 11 image in your USB drive. 🎉

Useful Links:

• Windows 11
• wimtools
• Split image documentation
• Format USB Drive
• Balena Etcher
• Ubuntu