To install the bios bootloader: grub-install --force --removable --boot-directory=/mnt/usb/boot --target=i386-pc /dev/loop0 To install the EFI bootloader: grub-install --force --removable --boot-directory=/mnt/usb/ --target=x86_64-efi --efi-directory=/mnt/usb /dev/loop0 To test bios: kvm drive.img To test EFI: kvm -bios /usr/share/ovmf/OVMF.fd drive.img

• https://github.com/aguslr/multibootusb/blob/master/mbusb.d/debian.d/live9-generic.cfg

• https://www.pcsuggest.com/create-a-multiboot-usb-drive-with-grub-in-linux/