Make multi OS bootable USB drive including windows os and linux

Using DiskPart combined with a BIOS/UEFI hybrid approach is a very manual method to make multi OS bootable USB on Windows 10 or Windows 11. This approach involves partitioning and formatting the USB drive with DiskPart, then setting it up to support both BIOS and UEFI boot modes, allowing you to boot multiple operating systems from a single USB.

Process:

1. Use DiskPart to create two partitions on the USB: one large NTFS for Windows/Linux files, one small FAT32 (≥300MB) for UEFI boot.

2. Make the FAT32 partition active. Use bcdboot to install Windows boot files to it.

3. Copy the entire contents of a Linux ISO (like Ubuntu) to the NTFS partition.

4. Manually edit the BCD store on the FAT32 partition to add a entry pointing to the Linux kernel (vmlinuz) and initrd (initrd.img), or use a tool like BOOTICE to manage the BCD.

5. This creates a USB that boots to a Windows-style boot menu, letting you choose between booting into the Windows installer environment or launching a Linux installer.

About making multi OS bootable USB on Windows PC. This is a bare-metal, forensic-level approach to building a multi-boot environment, treating the boot process as a series of components to be assembled by hand.