Comment by josteink
4 months ago
> It seems you also need to make the USB stick bootable?
That’s for legacy MBR boot. It has no function with UEFI boot.
Same for Windows as it is for Linux.
4 months ago
> It seems you also need to make the USB stick bootable?
That’s for legacy MBR boot. It has no function with UEFI boot.
Same for Windows as it is for Linux.
Interesting. This is the first traditional UEFI machine I’ve had. Anything prior to this has been Seabios/Coreboot in recent times.
TLDR: UEFI just checks in NVRAM for pre-existing boot-configs (stored paths to EFI-executables for installed operating systems) and if doing "dynamic" booting from some random media, it checks if the the volume has a EFI-executable for the given architecture (for instance in \BOOT\bootx64.efi for Intel x64), and if it does, it loads that file.
UEFI usually boots straight into native long mode without any weird 8086 compatibility modes being employed (which the OS then has to unroll), so for the OS its simpler to deal with.
It can also serve as a multi-boot menu on machines which has several OSes installed.
It often comes with a MS-DOS like "UEFI Shell" you can boot into... To manage UEFI itself. So if something doesn't boot, you can just boot into the shell instead and try to fix things from there.
It may sound complex, but once you get into it, its really much easier to work with that legacy MBR boot, and all the "magic" things you have to do their to get things booting.
I definitely recommend reading up on it.