Also, on newer machines with USB3 controllers it is necessary to add the xhci_hcd driver (built into the kernel or as a module). When there are lots of modules booting takes a long time so it probably does not matter, but if there are only a few modules loaded then it is important, because the system could have booted before the kernel detects the USB device.
I had an opportunity to learn how to boot from USB using GRUB. Moreover, ever since I installed GRUB, the shortcut to summon booting device selection stopped working. I prepared a USB stick with the new system, but I couldn’t boot from it – BIOS was restoring the booting order on every reboot. I use it from time to time, but one day the filesystem crashed, and even fsck couldn’t repair it. One of my old computers runs Linux with GRUB as a bootloader. But what if both options failed for some reason? If not, there is an option in BIOS/UEFI to change that. Almost every modern computer has a dedicated menu to choose from which device the system should boot.