All the recent threads about both BIOS and UEFI booting
got me interested in playing with making a USB stick
that can boot practically anywhere.
The instructions here kinda work:
https://wiki.archlinux.org/index.php/Multiboot_USB_drive
I can boot the USB stick on something like a windows
machine that has no existing grub installation.
But if I try booting it from a linux box, it apparently
searches for and finds the existing grub on the system
and goes there to boot instead of using the grub
config on the USB stick (which sort of defeats the
purpose :-).
Anyone know how to install grub and force it to search
for the UUID of the root partition on the USB stick
and not any other device that just looks like grub?
That's up to the grub.cfg contents. I'd you look at any Fedora grub.cfg including on ISO install media, you'll see it searches for a UUID, this is where to find the kernel and initramfs. If that UUID isn't found it fails, grub prompt. Grub doesn't look around unless expressly told to in the grub.cfg
I think what you're experiencing, is the BIOS setup is set to boot from some other drive, not USB. So you need to change this in BIOS setup.
Chris Murphy