How to multiboot USB with Windows 11, Windows 10 and Linux

Using a manual GRUB2 setup to create a single multiboot USB drive for installing Windows 10, Windows 11, and a Linux distribution is a versatile and efficient approach. It allows you to have all your installer images in one place, with a custom menu to select which OS to install. Here’s an overview and step-by-step guide, including the key phrase "how to multiboot USB" for your narration.

How to Multiboot USB: Creating a Custom GRUB2 Multiboot Drive

1. Prepare the USB Drive

• Format the USB drive to FAT32 or exFAT (FAT32 preferred for UEFI boot compatibility).
• Use tools like GParted (Linux) or Disk Management (Windows) to format and create a single FAT32 partition.
• Make the partition bootable if your tool allows.

2. Copy ISO Files to the USB

• Mount the ISO images.
• Copy the ISO files into a dedicated folder, for example, /ISO/.

3. Install GRUB2 Bootloader

• On a Linux system, install GRUB2 if not already installed:

sudo apt-get install grub-pc

• Mount your USB drive and install GRUB:

sudo mount /dev/sdX1 /mnt # replace sdX1 with your USB partition

sudo grub-install --target=x86_64-efi --efi-directory=/mnt --boot-directory=/mnt/boot --removable

4. Configure GRUB2 Menu

Create or edit the GRUB configuration file (/mnt/boot/grub/grub.cfg) with entries for each OS. For example:

set timeout=10

menuentry "Install Windows 10" {

insmod part_msdos

insmod fat

loopback loop /ISO/windows10.iso

linux (loop)/boot/grub/loopback.cfg

}

menuentry "Install Windows 11" {

insmod part_msdos

insmod fat

loopback loop /ISO/windows11.iso

linux (loop)/boot/grub/loopback.cfg

}

menuentry "Install Linux" {

insmod part_msdos

insmod fat

loopback loop /ISO/linux.iso

linux (loop)/casper/vmlinuz boot=casper iso-scan/filename=/ISO/linux.iso quiet splash

initrd (loop)/casper/initrd.lz

}

5. Finalize and Test

• Safely unmount the USB.
• Boot from the USB in UEFI or Legacy mode.
• The GRUB menu should appear, allowing you to select the desired installation.