[lfs-support] EFI, UEFI and LFS--Complicated, Confusing or Can of Worms

Geoff Swan gswan3 at bigpond.net.au
Fri Nov 1 12:50:34 PDT 2013


That works for me too. Using a 64-bit kernel and creating the EFI file
in the efi partition with the kernel boot parameters built into the kernel.
Also built efibootmgr utility.

On 1/11/2013 11:13 PM, Craig Magee wrote:
> I use UEFI by putting the kernel and an (optional) initrd in the EFI
> partition.  The kernel has EFI stubs if you enable the option.
> You can pass kernel parameters in the UEFI boot entry or put them in
> the kernel itself.  Both options are available towards the bottom of
> 'Processor type and features' in the kernel configuration.
> The only gotcha is booting 32-bit, my UEFI system only supports
> booting 64-bit so I had to install a 64-bit GRUB to then boot a 32-bit
> kernel.
>
> I find UEFI is actually pretty neat and removes the need for an
> additional bootloader.  Anytime I want to boot anything other than the
> default (including from CD or USB) I press the escape key and select
> the option I want.  GPT partitioning rocks as well (though you don't
> need to use UEFI to take advantage of that using Linux; you do for
> Windows).
>
>
> On 31 October 2013 06:02, Casey Daniels <mailinglist at cd.kcfam.net
> <mailto:mailinglist at cd.kcfam.net>> wrote:
>
>
>     On 10/30/2013 12:47 PM, Dan McGhee wrote:
>     > On 10/30/2013 11:26 AM, Casey Daniels wrote:
>     >> On 10/30/2013 12:17 PM, Dan McGhee wrote:
>     >>> Anyway, I just wanted to share what I have discovered.  This
>     may lead to
>     >>> posts like, "I did this and it didn't work.  The book needs to be
>     >>> changed."  The implementation of LFS, configuring and
>     installing both
>     >>> the kernel and GRUB can be successful regardless of how the
>     BIOS boots.
>     >>> There is a learning curve though. And some of GRUB's building and
>     >>> installing arguments need to be a little different.
>     >>>
>     >>> Dan
>     >>>
>     >> I played with UEFI Boot for almost a week and couldn't get
>     anywhere with
>     >> it.  I could get Grub Loaded, and and I could get grub to find the
>     >> Kernel, but then it would ALWAYS fail at some memory point
>     during the
>     >> Kernel load, and I played and played with the kernel for that
>     week and
>     >> it keep freezing at the same point.
>     >>
>     >> The thing with UEFI Boot is you don't need Grub to boot if you
>     don't
>     >> want to.  If you have a Linux only or Windows only, computer
>     you can
>     >> actually boot with out user input without a bootloader.  From my
>     >> understanding though if you have a dualboot system you need at
>     a minimum
>     >> a boot manager to boot without user intervention.  If you don't
>     mind
>     >> typing a few commands you can boot with out a boot manager or
>     bootloader
>     >> in a dual boot system, you just have to understand the UEFI
>     Shell you get.
>     >>
>     >> Casey
>     > Casey, your experience confirms what I have learned by reading
>     and my
>     > own experience. Yes, on dual boot you need a manager to get to the
>     > loader you want. That's one of the functions of the EFI partition. I
>     > don't want to address your specific situation until I have practical
>     > experience with my LFS build and that won't be for a couple of
>     more days.
>     >
>     > If you have not been successful in booting your LFS system and
>     you want
>     > to "play," I recommend turning off secure boot, checking your kernel
>     > configuration to support efi and running <grub-install --help>
>     to select
>     > the arguments you use for grub. I just finished reading
>     "grub-install"
>     > and it looks like it should detect your partition type--MBR or
>     GPT. I
>     > don't want to suggest anything definite because I haven't
>     "proved" them
>     > with my own experience. One of the possible outcomes is that your
>     > computer won't boot. I would rather be the victim of my own
>     eperiments
>     > rather than having someone else be that victim. :)
>     >
>     > Dan
>     >
>          I had no problem getting the Boot Loader working, surpurising
>     enough, though I did learn that in order to get grub to do a
>     proper UEFI
>     Install, the system your installing it from had to have booted from
>     UEFI.   I had Grub find the Kernel in the proper place, and start to
>     load, but the Intel board I use does some type of Memory Check and
>     always fails at the same Memory Address.  So I don't know if I had
>     some
>     incompatable Option in my Kernel or there is a issue with Intel's UEFI
>     Implentation (Which from what I was able to read on the subject this
>     might be the case, I think it trys to protect that Memory Address and
>     the Linux Kernel trys to get into that specific Address).  Yes I did
>     have Secure boot turned off.
>          I really don't care about UEFI boot for the current hardware
>     of my
>     servers, but from my understanding is my Intel Boards are UEFI boards
>     that emulate the orginal BIOS for Compability reasons, however some
>     boards are already coming out as UEFI only and it probably won't
>     be too
>     long before most boards don't have a legacy mode.
>
>     Casey
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