A usb drive with only 1 partition to load grub2 on usb-bootable machines with Legacy BIOS, 64bit UEFI or 32bit UEFI.
Note: due to the maximum size of a file inside an EFI system partition, files (such as ISO disk images) of 4 GiB or larger must be placed on another partition. That second partition can be of type ext4, for instance.
Partition the drive and install grub2
Warning: the usb drive will be formatted, save your data before proceeding!
First of all, on you current installation, check if the folder /usr/lib/grub/ exists and is not empty. If it is empty or does not exist, make sure the package grub-common (or equivalent for your distribution) version 2 or higher is installed. Depending on the system, /usr/lib/grub/ will contain one or more of the following folders: x86_64-efi, x86_64-efi-signed, i386-pc, i386-efi, …
The x86_64-efi, i386-pc and i386-efi folders need to be present in order to install the corresponding bootloader on the usb drive. Continue reading