How to Create a EFI/UEFI GRUB2 Multiboot USB drive to boot ISO images

[sudodus]

Build your own single boot or multiboot pendrive for all PC (Intel/AMD) computers

I made a system, where a shell-script helps performing the operations, that are described in this thread. I found that it is possible to do everything in either UEFI mode or BIOS mode, the two grub installations are simply done with two different command lines.

$ grep grub-install mk-grub-n-iso 
grub-install --force --removable --no-floppy --boot-directory=/mnt/target/boot --efi-directory=/mnt/target/EFI/BOOT "$2"
grub-install --force --removable --no-floppy --boot-directory=/mnt/target/boot "$2"

This works in an Ubuntu family operating system of version 14.04 LTS or newer. (It is possible to use Ubuntu 12.04 LTS too, but it has an older version of grub, and I have not found a method to make pendrives that boot in both UEFI and BIOS mode.)

This link describes how to install and use this system,

Build your own single boot or multiboot pendrive for all PC (Intel/AMD) computers

[Starbeamrainbowlab]

Is it possible to do this and allow windows to mount the partition?

Currently if I plug the flash drive into windows I get an "EFI System Partition" which I can't mount under windows 7.

If not, can I create a second "main" parition to store data & ISOs on?

[sudodus]

The EFI partition must have a FAT file system. Linux works best with linux file systems but Windows cannot mount partitions with linux file systems. So in order for Windows to mount them, you need FAT or NTFS file systems. If you want access the ISO files from both linux and Windows, I would recommend using the FAT32 file system (for the partition where you keep the ISO files).

Yes, you can create a second (or third etc) partition if you wish, but avoid storing the ISO files in two places.

Edit: There is one thing I should add - At least some versions of Windows have problems to mount more than one partition on USB drives. (I don't know if it affects all versions of Windows.) It wants to open the first one, but I am not sure what happens if the first partition is recognized as an EFI partition. I just checked: Windows 7 will only recognize the first partition (the EFI partition). Some other Windows version might mount the second partition, if it has a Windows file system. But to be sure, make a big first partition with the FAT32 file system, and keep the ISO files there, if you want them to be available from Windows.

[Starbeamrainbowlab]

Update:

By changing the partition to "0700" (A basic data partition) I can boot using UEFI + BIOS, but I can also see it in Windows.

[sysmatck]

Update:

By changing the partition to "0700" (A basic data partition) I can boot using UEFI + BIOS, but I can also see it in Windows.

Yes, I did some testing. I can also boot using 0700 as partition type. When using 1:ef00 the partition will not automount on Linux. But with 0700 it is mounted automatically. I supose this is an interesting information, if you want a partition to automount, maybe 0700 is a better option. If this will be just a boot partition, you might prefer not to mount...

[sysmatck]

Hello Again!

I just wanted to report that I'm being able to boot with UEFI/BIOS mode with a dual partition USB stick. The first partition is EF00 and the second one EXT4(8300). The boot and EFI directories were stored on the first partition e.g. /dev/sdb1 and the iso directory is located on EXT4 partition e.g. /dev/sdb2

I can boot with GRUB2 using the following code

menuentry 'Lubuntu 14.04 i386' {
		set isofile="/iso/lubuntu-14.04.2-desktop-i386.iso"
		loopback loop (hd0,2)$isofile
		linux (loop)/casper/vmlinuz boot=casper iso-scan/filename=$isofile liveimg noprompt noeject quiet splash --
		initrd (loop)/casper/initrd.lz
	}

Note the difference on "Loopback" line... This is it!

[sudodus]

Yes, it works

I've done something similar as described in post #11 (and the link from there)

and also at the following link: mkusb/persistent

[Elvizk]

I tried this method but I cant able to boot Hiren boot iso.

[michael300]

Excellent write-up, very helpful. I've been looking for a solution to be able to have a multi-boot capable to run on EFI systems and legacy. I was wondering if it would be possible to boot a version of windows with this setup? I was able to get a multi-boot system through yumi that allowed me to chainload windows as well, however, yumi doesn't support efi/uefi systems... I'll do some tinkering to see if I can get it to work, but I was hoping somebody could point me in the right direction. Thanks!

[oldfred]

Windows will not boot from USB devices.

You can possibly create installer or repair disk with Windows but have to install it first then reconfigure with grub & ISO files.
I did create a BIOS Windows 7 repair flash drive. But it used so little space that I then decided to try to add grub & ISOs.
The main issue is the grub creates a /boot folder & Windows has a /Boot folder. In Linux case matter, but in Windows is does not. So you must have all files in same /Boot or /boot folder, but not both as Windows will not work with two /boot folders.