Do I need UEFI

[D-Dan]

Having got my rebuild working, booting legacy BIOS, and working, do I need to convert to UEFI? Will it add anything, and will I notice?

Arch Linux, on a Ryzen 7 1800X, 32 GB, 5 (yes -5) HDs inc 5 SSDs, 4 RPi 3Bs + 1 RPi 4B - one as an NFS server with two more drives, PiHole (shut yours), Plex server, cloud server, and other random Pi stuff. Nice CoolerMaster case, 2 x NV GTX 1070 8GB, and a whopping 32" AOC 1440P monitor.

[Ed P]

You will certainly notice, and it may improve your head-banging and Chakras! If you forget to make a uefi bootable stick it will make any system restoration an interesting challenge!

Joking aside, a uefi bios normally allows far more low level configuration of the system and hardware. Whether you will use it more than once I personally doubt, but it does allow you to twiddle around if overclocking or energy conservation are your bag. Above all uefi adds far more low level security and really comes into its own on a lap-top.

[D-Dan]

So basically, on a desktop system, not worth the effort?

Arch Linux, on a Ryzen 7 1800X, 32 GB, 5 (yes -5) HDs inc 5 SSDs, 4 RPi 3Bs + 1 RPi 4B - one as an NFS server with two more drives, PiHole (shut yours), Plex server, cloud server, and other random Pi stuff. Nice CoolerMaster case, 2 x NV GTX 1070 8GB, and a whopping 32" AOC 1440P monitor.

[keith with the teef]

Obviously make sure what ever bios you r using that it supports AHCI.

well if using an SSD.

[Ed P]

D-Dan wrote:

So basically, on a desktop system, not worth the effort?

It depends how hard you think it will be, and how important it is to have a secure system. Maybe for the average user a couple of hours would be well spent. From my reading converting a system to uefi is fraught with issues, most seem to advise a clean start.

This comment is made in ignorance of just how hard it is to incorporate uefi in a Linux distro. As to be honest I have never used uefi with Linux. I do not have to take that action, having neither a business, banking or secrets I need to protect beyond the usual off-site backup. In any case setting up uefi with Windows verges on the trivial.

At heart uefi is a low-level security system. I’m afraid that even on Linux the MBR has become almost trivial for script kiddies to attack, of course they have to devise a vector, but unless your Linux is very securely locked down a determined spear-phisher could probably get in and cause havoc.

[Wheels-Of-Fire]

http://www.uefi.org/specsandtesttools

Have a look at the above link and the links it leads to. This is the least complicated info I can find that still goes into some depth. UEFI is a lot like a framework for EFI apps and most of the parts are optional. Secure boot is optional and even a GUI interface is not actually required. A UEFI BIOS must impliment the entire framework though before it can add any EFI modules such as a GPT boot loader.

You may also notice that the working group now controls the ACPI spec too.

[Wheels-Of-Fire]

A framework for apps and drivers I should have said. Pre boot apps are unloaded when UEFI passes control to an OS but drivers remain and are available to the OS through UEFI function calls. This is a good way of finally getting rid of option ROMs on expansion cards amongst other things as an OEM can supply a UEFI driver that gets installed in the EFI partition on your boot drive. UEFI even supplies its own command shell to enable such things to be done manually, pre boot.

[Ed P]

Just to add to Wheels latter comment, mobo makers sometimes provide low level uefi modules that monitor drivers and update them and the bios as required. (Asustek is a good example, but probably Windows only).

[Wheels-Of-Fire]

I don’t know for sure Ed, but Linux supports UEFI so it must support UEFI function calls and return codes. UEFI hardware drivers are also written to conform to the UEFI interface so with the UEFI framework between the driver and the OS the whole thing SHOULD be universal ?

[Ed P]

Probably you are correct, but according to Phoronix, support is limited. As always, the devil is in the interface code. It depends how Linux support has developed over the years but the early Phoronix advice was to use Windows to sort out motherboard issues.

Since that time, UEFITool has appeared and maybe this would bridge the gap.

[D-Dan]

I’m guessing that UEFI is simply a cure for a problem that MBR/GRUB doesn’t have. I have nothing starting at early boot, other than to make sure my system boots. i.e. a basic Input/Output system. In otherwords, BIOS hands over to the boot system (in my case GRUB), and that’s it.

I suspect UEFI could prove to be more of a security problem than I have now. The biggest risk to me, is something hijacking GRUB. Converting to UEFI could open that hole up.

EDIT. I say that because UEFI boot will take kernel control away from the user, and hand it over to the base system.

Arch Linux, on a Ryzen 7 1800X, 32 GB, 5 (yes -5) HDs inc 5 SSDs, 4 RPi 3Bs + 1 RPi 4B - one as an NFS server with two more drives, PiHole (shut yours), Plex server, cloud server, and other random Pi stuff. Nice CoolerMaster case, 2 x NV GTX 1070 8GB, and a whopping 32" AOC 1440P monitor.

[Wheels-Of-Fire]

Again things SHOULD be getting better as time goes by.

System configuration and power management problems were ment to be sorted with the release of ACPI but the spec was too lax and open to interpretation.

UEFI is meant to totally replace the software side of ACPI at some time in the future but to ease the transition BIOS writers are still able to specify legacy ACPI as an option. The OS can query the UEFI options installed with a function call and act accordingly.

In the meantime responsibility for ACPI development was transferred to the UEFI Forum in 2013 and they have been busy tightening up the spec, especially on the hardware side as that will remain into the future.

 

[Ed P]

OK then maybe the question for you is whether you need GPT and disks of 2TB+.

For backups I certainly find being able to use huge disks a useful plus. (I tend to use the old three version  backup rotation which gobbles up disk space)

[Wheels-Of-Fire]

Just for completeness, I forgot to mention that UEFI is 32 bit code and hands over to the OS loader with the CPU in protected mode. No part of the loader now runs in 16 bit mode (so you need a different loader) as it can make UEFI calls instead of using old style BIOS interrupts.

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