🧰 Requirements

A Linux host with:

• qemu (or qemu-system-x86_64) installed
• sudo privileges
• The ISO file of the OS you want to install (e.g. ubuntu.iso)
• A USB drive (we’ll call it /dev/sdX — replace X with your actual device letter)

⚠️ Be careful — this process will overwrite all data on the USB drive.

You can identify the USB drive with:

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lsblk

Then note your target (e.g. /dev/sdb).

🧩 Step-by-step using QEMU

1. Unmount the USB drive (important!)

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sudo umount /dev/sdX*

2. Run QEMU, booting from the ISO, using the USB drive as the VM’s hard disk

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sudo qemu-system-x86_64 \
  -enable-kvm \
  -m 4096 \
  -boot d \
  -cdrom /path/to/installer.iso \
  -drive file=/dev/sdX,format=raw,if=virtio \
  -vga virtio

Explanation:

• -enable-kvm → hardware acceleration
• -m 4096 → 4 GB of RAM
• -boot d → boot from CD-ROM first
• -cdrom → ISO installer
• -drive file=/dev/sdX,format=raw → use the physical USB as a raw disk
• -vga virtio → decent graphics for most installers

3. Install normally
Inside the VM, choose the target disk corresponding to the USB drive (usually shows as /dev/vda in the VM).
Perform the OS installation as you would on a normal hard drive.

4. Shut down the VM
Once the installation finishes, power off the VM.
You can then safely remove the USB and boot it on real hardware.