It works fine except when it doesn't, which is most of the time (either secureboot, or the EFI boot manager, or the Windows 8+ "fast startup" thing that can turn itself on during an update and sets the EFI next-boot option, permanently overriding any GRUB selection until you turn it back off from inside Windows..)
Compared to how hassle-free multiple operating systems is to do via legacy boot, UEFI feels incredibly backward. It feels unfinished, is fragile and breaks far too easily for something so critical.
I'm not looking forward to it being taken away. Guess I'll have to ditch my other OSes and do my important work in a VM.
> Windows 8+ "fast startup" thing that can turn itself on during an update and sets the EFI next-boot option
Clearly annoying, but easily fixed.
I'd rather have this once a year than Windows deciding it has the right to write to my MBR, and overwrite GRUB, causing my Linux installation to be unbootable without a recovery-disk.
> Compared to how hassle-free multiple operating systems is to do via legacy boot
That may be true for multi-volume scenarios. For systems with one volume only however (like most laptops), it's absolute the opposite.
> It feels unfinished, is fragile and breaks far too easily for something so critical
My experience is quite the opposite. With UEFI I feel I can fearlessly dual/multi boot several operating systems without fear that one OS is going to mess up another one.
And I know that if something happens once a leap year or so, EFI has proper tooling so it's easy to fix, unlike black-boxed MBR bootloaders and the hacks involved with chain-loading different OSes on top of them.
1. Windows will decide to undo your boot settings or grub every now and then? How can it do that, and can Linux do it too? If UEFI is "secure", is there no way to securely prevent windows from changing it?
2. UEFI does NOT support multiboot on multiple volumes? You cannot install different OSes on different disks? What if you put multiple SSD's and HDD's in a desktop computer, can you install a different OS on each and boot to any with UEFI? What about booting from USB sticks?
1. Any OS can update which UEFI boot-target is the default one (this is what parent poster complains about). It should however not interfere with another OSes config or files. Windows does not touch Grub (or the other way around). That messy, unsafe and unreliable approach is reserved for legacy BIOS boot.
2. UEFI supports clean and safe separation between boot-targets, across single volumes, multiple volumes and networks targets with cryptographic verification if desired (Secure boot). UEFI supports everything traditional BIOS boot supports and more. The same can not be said the other way around. It also boot straight into long-mode, meaning you don’t have to implement X86 mode-golf (and similar lessons in ancient history) at all in your OS-loader.
UEFI is rather overengineered, but it’s clearly a better approach with better support for modern use-cases built into the core design.
Think of UEFI as Grub built into your machine. With UEFI your individual OS’s bootloader should no longer need to handle/be aware of multi-booting. They should only boot themselves.
UEFI has no issues with multi-volume setups. They are hassle free.
My focus one single volume setups was really because this is where traditional legacy BIOS boot gets messy and unreliable if you want to setup dual/multi-booting, and UEFI is objectively superior in every way.
Biggest one by far is the super-ambiguous "boot failed" with nothing else while trying to get back into windows after turning off Fastboot (see step 7 in my other post). Once you've got that, you can fix it for the next boot with bootrec /FixBoot & /RebuildBCD, but it'll keep coming back every time its restarted. Only failsafe fix I've ever found that keeps it from coming back is to move everything, including GRUB itself, onto separate disks. At that point it cooperates, at least until Windows thoughtfully turns FastBoot on for you again.
A close second is secureboot's "invalid signature detected". You get the same message when you try to chainload off a non-present drive or one that isn't bootable, but if you make the non-booting disk the only one, suddenly it'll start working again. Usually a grub2 reprobe/reinstall will fix this, but its really annoying. The dual-OS desktops at work all get this upon reboot whenever we lose power.
> Clearly annoying, but easily fixed.
Sure, until it resets itself at the next update, suddenly won't work when you turn it back off and you have to do everything all over again...
> I'd rather have this once a year than Windows deciding it has the right to write to my MBR, and overwrite GRUB, causing my Linux installation to be unbootable without a recovery-disk.
Only there's no risk of your linux installation being completely hosed in this scenario, like there is for the Windows environment with UEFI thrown in. Instead of starting over from scratch/backups, you just have to mount your drives, re-probe and install GRUB. That takes maybe a few minutes. Also, in a multi-volume system it can be completely avoided by disconnecting your dedicated GRUB disk for windows updates; the same can't save you from Windows declaring itself king of the computer and suddenly turning on UEFI settings that you don't want.
> That may be true for multi-volume scenarios. For systems with one volume only however (like most laptops), it's absolute the opposite.
Its worse on single-volume scenarios, since you can get completely screwed. In a multi-volume environment, UEFI's fragility is somewhat compensated for by the fact you can boot off the boot sectors of the individual drives when it breaks.
> My experience is quite the opposite. With UEFI I feel I can fearlessly dual/multi boot several operating systems without fear that one OS is going to mess up another one.
Huh. Yeah, that's ... pretty much the exact opposite of the experience I and everyone I know has had. You're honestly the first person I've seen that's been a fan.
I’ve used separate EFI system partitions for Windows and Linux, since as you point out, Windows may not be a entirely good citizen all the time here.
At first I tried to force all OSes to use the same EFI partition (because why should they need different ones?), and yes, I now recall having some issues back then.
After that I tried to let Windows have it’s own EFI partition. That was also the default setup created when installing Windows last, so it really didn’t take any effort.
And that has worked flawlessly for me. You may want to give it a shot.
UEFI was pretty much designed to solve the multi boot issue in a clean way where different OSes don’t step on each other’s toes and creates issues.
This has worked fine from day one, even from a single physical volume.