[arch-general] UEFI experience - recommendations needed.

[Curtis Shimamoto]

On 01/05/13 at 09:41pm, Mike Cloaked wrote:
> On Sat, Jan 5, 2013 at 9:08 PM, Curtis Shimamoto <
> sugar.and.scruffy at gmail.com> wrote:
> 
> >
> >
> > From what I have been reading in the forums of late, apparently rEFInd
> > has a driver to read ext2 partitions, so can read your kernel/initramfs
> > from there.
> >
> > Also, srs5694 has indicated that the git version of rEFInd now has a
> > driver to read ext4 as well.
> >
> > --
> > Curtis Shimamoto
> > sugar.and.scruffy at gmail.com
> >
> 
> Thank you for both replies, Curtis - your comment about a systemd service
> file to append .efi to the kernel implies that when there is a kernel
> update you need to either manually create the appropriate filename
> (presumably in the ESP area?) or have the service file run a command to do
> that (presumably once written it is automatic?)  after the kernel update?
> 
Most firmware seems to want any efi application to have '.efi' at the end
of it.  From what I have read, there are some instances in which this is
not necessary.  For instance, from the uefi shell, it seems to append
that for you if it is not there.  Also, the gummiboot entry on the
archiso does not have it either, so maybe gummiboot can do without.

I know that if you are using a direct efibootmgr entry, you will more
than likely need the '.efi' after it.  I use gummiboot now, but I still
have systemd set up to append that on every kernel update.  There are
some good instructions on how to set this up on the uefi wiki page.

> It sounds like the way forward is to set up with legacy and switch once the
> base install is done.  Also I usually in the past format the drive before
> the install with partedmagic booted from a usbkey - but from what I have
> read partedmagic won't boot from a key with uefi!  So if I start out with
> normal BIOS and do disc partitioning, as well as flashing the BIOS with
> updated firmware from a bootable dos key then I guess the main install
> should be as normal - and if it boots with legacy BIOS set with GPT
> formatted drives then it would hopefully not be too much work changing over
> to EFI at that stage.
> 
Yes, this should be fine.  It does not matter how your system is booted
when you do the partitioning. The only time you need to actually boot into
UEFI is in order to create bootloader entries.  This is because the
efivars module must be loaded in order for your machine to access the
nvram, and the module cannot be loaded unless you are booted with UEFI.

A simple way around this is by using the default efi application.  If you
choose to boot from the disk itself, and have it set to boot UEFI, it
will boot whatever is located at \EFI\boot\bootx64.efi.  So you can put
whatever you want there.  

When I first began using UEFI, I had the UEFI Shell there so that I could
always fall back to something versatile.  But now that I have gummiboot
set up the way I like it, I have gummiboot there instead.
> From what I read if using rEFInd then Grub is not needed but am still
> reading!
> 
Yes, rEFInd is a boot manager, while grub is both a boot loader and a
boot manager.  The boot manager part is the selection menu, the loader
part is actually loading the kernel.  But the kernel now features stub
loader support, which enables it to act as its own bootloader.  Hence you
can make an entry directly into your bios' nvram to boot the kernel
directly (using efibootmgr).  Instructions are also in the wiki.
> -- 
> mike c

-- 
Curtis Shimamoto
sugar.and.scruffy at gmail.com