UEFI worth the troble?

[mos4567]

Hi! :)

I am getting ready to move a desktop from 10.04 to 10.10. The motherboard is an intel DP55KG. Currently, the system has a problem I have yet to find a solution to, if halted it will turn off fine but if rebooted it will hang forever after requesting a system restart.

The board supports "EFI boot" as an option you can toggle. I have it off because I could not even get the install CD to boot when I installed 10.04 but with it off everything works except for that rather annoying reboot problem, it only really become bothersome after installing an update that requires a reboot because it is easy to just forget and click reboot.

Now then I am going to be installing 10.10, it seems time to give the problem a fresh crack. I have wondered if the problem might go away if I was using the UEFI, but before I spent some time attempting to figure out how to boot the install CD when UEFI is on and then install correctly, I wanted to see if people felt I was barking up the wrong tree in my attempts to alleviate this problem.

I have done some googling on installing with UEFI and I have found a lot of information regarding the EFI Apple Macs use, but it also seems that UEFI, an Intel technology, is little different animal. Should I follow steps along the lines of the ones for the Mac EFI or is someone aware of a UEFI specific resource / has personal experience with UEFI?

Thanks for your help!

[srs5694]

Apple Macs use a slight variant on EFI 1.x, but most x86 systems with EFI use UEFI 2.x, which is a more recent version of the same thing. (Apparently Apple's EFI has a few Apple-specific tweaks, too.)

I don't know whether switching to UEFI would help your rebooting problem or not. If you do switch, you'll be a bit of a trail-blazer, so I'd only recommend it if you're willing to spend some time experimenting. The biggest problems are likely to relate to partitioning and boot loader configuration.

EFI (including UEFI) introduces a new partitioning system, known as the GUID Partition Table (GPT). UEFI doesn't require GPT, so in theory you should be able to continue to use the older Master Boot Record (MBR) system you're probably using now; however, UEFI does require (or at least strongly recommend; I don't recall which) a special partition known as an EFI System Partition (ESP), which is about 100-200 MiB in size with a FAT32 filesystem on it. Thus, if you want to preserve your existing partitions, you may need to trim one of them a bit to make room for an ESP. Give it a type code of 0xEF if you keep using MBR. If you decide to go whole-hog and switch to GPT, you can do it non-destructively with my GPT fdisk (http://www.rodsbooks.com/gdisk/) utility. You can boot BIOS-based systems from GPT, so if you try EFI and then decide you don't like it you should be able to switch back to BIOS; however, some Intel BIOSes have known problems that require workarounds (http://www.rodsbooks.com/gdisk/bios.html) to boot from GPT disks. Note that if you dual-boot with Windows, it requires GPT to boot from EFI. Switching from one to the other under Windows is likely to be tricky, but see this forum post (http://www.insanelymac.com/forum/index.php?showtopic=186440%20.) for information on making such a transition.

In terms of booting, GRUB 2 supports EFI, but this support seems to be a bit new. Most Mac users seem to be using something called rEFIt, but I'm not sure if that's Mac-specific or if it works with UEFI-based PCs. The older ELILO is also an option. I'm afraid I don't know much about the specifics of these boot loaders, since I don't (yet) have an EFI-based system. (I've got a used Intel-based Mac Mini on the way, though.)