GRUB2 on efi32 - Apple Mac Mini

GRUB2 on efi32 - Apple Mac Mini

[Michal Suchanek]

Hello

I tried installing GRUB2 on a Mac mini.

There are issues on this platform, and it seems they are too
fundamental to resolve over IRC.

I have installed

OS X 10.4

reFit (some older version which I installed some time ago to make the
system reasonably multibotable).

I could not get the PC version of grub (Debian testing package) to
work with reFit + Apple BIOS emulation - Linux failed to boot as
legacy system. Previously I was using the NetBSD loader which worked
fine.

I installed the efi32 grub version (followed the TestingOnMacBook page
of the wiki, built the grub on a LiveCD and copied the files to the OS
X over network).

Now I can
 -- bless grub with the OS X bless command
  this makes GRUB the default (only) boot loader until OS X next
starts, when OS X boots it makes reFit the default (only) loader again
 -- load GRUB from reFit
  this starts GRUB but the menu is not loaded.
  I can load it with
     configfile /efi/grub/grub.cfg
  or
    chainloader /efi/grub/grub.efi

 Loading reFit from GRUB works about every other time but loading
grub, OS X, or the efi32 GRUB from Debian works always. The Debian efi
GRUB is not seen by reFIT, it probably does not understand ext2.
Interestingly, it also does not see the copy of GRUB in my home on OS
X which should be complete, including a config file.

 Booting legacy systems no longer works - a message that no system
disk is available is always displayed, only with a PC CD inserted the
CD is booted regardless of the legacy media specified in GRUB or reFit

I also did not find any option for rotating the GRUB output to match
the way the display is mounted. As I understand it GRUB uses the
'console' menu by default which is very simple but as there is no PC
bios at this point it still has to draw the characters, right?

Thanks

Michal

RE: GRUB2 on efi32 - Apple Mac Mini

[James Shewey]

3 questions:

1) what is the FULL bless command that you are using
2) for the issue where grub is not seeing your home directory, what modules do you have running (lsmod should show this) 
3) and finally, what is your prefix and root ( type set to see this and other environment vars)

-----Original Message-----
From: Michal Suchanek <hramrach@centrum.cz>
Sent: Tuesday, December 09, 2008 5:16 PM
To: grub-devel@gnu.org
Subject: GRUB2 on efi32 - Apple Mac Mini

Hello

I tried installing GRUB2 on a Mac mini.

There are issues on this platform, and it seems they are too
fundamental to resolve over IRC.

I have installed

OS X 10.4

reFit (some older version which I installed some time ago to make the
system reasonably multibotable).

I could not get the PC version of grub (Debian testing package) to
work with reFit + Apple BIOS emulation - Linux failed to boot as
legacy system. Previously I was using the NetBSD loader which worked
fine.

I installed the efi32 grub version (followed the TestingOnMacBook page
of the wiki, built the grub on a LiveCD and copied the files to the OS
X over network).

Now I can
 -- bless grub with the OS X bless command
  this makes GRUB the default (only) boot loader until OS X next
starts, when OS X boots it makes reFit the default (only) loader again
 -- load GRUB from reFit
  this starts GRUB but the menu is not loaded.
  I can load it with
     configfile /efi/grub/grub.cfg
  or
    chainloader /efi/grub/grub.efi

 Loading reFit from GRUB works about every other time but loading
grub, OS X, or the efi32 GRUB from Debian works always. The Debian efi
GRUB is not seen by reFIT, it probably does not understand ext2.
Interestingly, it also does not see the copy of GRUB in my home on OS
X which should be complete, including a config file.

 Booting legacy systems no longer works - a message that no system
disk is available is always displayed, only with a PC CD inserted the
CD is booted regardless of the legacy media specified in GRUB or reFit

I also did not find any option for rotating the GRUB output to match
the way the display is mounted. As I understand it GRUB uses the
'console' menu by default which is very simple but as there is no PC
bios at this point it still has to draw the characters, right?

Thanks

Michal


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Re: GRUB2 on efi32 - Apple Mac Mini

[peter cros]

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My current preferred bootloader is SVN version 1913 grub2.efi here on an
Apple MacBook2,1. running Macosx10.4 and Ubuntu810 i386 32bit kernel (2.6.27
kernel), together with rEFIt 0.12 (but also used standalone).

The amd64 kernel loaded but failed to complete initialization.

Glad to know grub.efi still runs on the mini.

To date I have not seen any reports of running on later MacBook versions.
and the apple efi refused to load grub.efi on a macbook3,1. I have been
trying to get Ubuntu forum people to test on other macs.

I can comment on some of the issues  mentioned.

The rEFIt blesser resets to bless rEFIt on exit from Macosx.
The explanation for this is on the rEFIt site.

rEFIt has a case problem. The efi directory, containing grub.efi and
refit.efi, needs to be upper case 'EFI' not 'efi', rEFIt confuses the case
in the prefix passed to grub, hence loss of the grub.cfg menu.

The failure to boot legacy bios may be associated with loss of MBR sector
partitioning table (happens with the ubuntu linux parted partitioner for
GPT/MBR disks). Check by a hexdump of the MBR sector.

I can't get grub.efi to load rEFIt using chainloader, but I don't want to do
that.

I find considerable advantage over grub-pc is separate installation, off the
linuix file system, and off the disk MBR sector, plus external drive
bootability. Requirement to disable accelerated graphics is a stopper for
some people. Pity it doesn't work on more macs.

Peter Cros

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Re: GRUB2 on efi32 - Apple Mac Mini

[Michal Suchanek]

2008/12/10 peter cros <pxwpxw8@gmail.com>:
> My current preferred bootloader is SVN version 1913 grub2.efi here on an
> Apple MacBook2,1. running Macosx10.4 and Ubuntu810 i386 32bit kernel (2.6.27
> kernel), together with rEFIt 0.12 (but also used standalone).
>
> The amd64 kernel loaded but failed to complete initialization.
>
> Glad to know grub.efi still runs on the mini.
>
> To date I have not seen any reports of running on later MacBook versions.
> and the apple efi refused to load grub.efi on a macbook3,1. I have been
> trying to get Ubuntu forum people to test on other macs.
>
> I can comment on some of the issues  mentioned.
>
> The rEFIt blesser resets to bless rEFIt on exit from Macosx.
> The explanation for this is on the rEFIt site.
>
> rEFIt has a case problem. The efi directory, containing grub.efi and
> refit.efi, needs to be upper case 'EFI' not 'efi', rEFIt confuses the case
> in the prefix passed to grub, hence loss of the grub.cfg menu.
>
> The failure to boot legacy bios may be associated with loss of MBR sector
> partitioning table (happens with the ubuntu linux parted partitioner for
> GPT/MBR disks). Check by a hexdump of the MBR sector.

yes, I will look at the rEFIt and MBR, thanks.

>
> I can't get grub.efi to load rEFIt using chainloader, but I don't want to do
> that.
>
> I find considerable advantage over grub-pc is separate installation, off the
> linuix file system, and off the disk MBR sector, plus external drive
> bootability. Requirement to disable accelerated graphics is a stopper for
> some people. Pity it doesn't work on more macs.
>

Acceleration works fine for me. The VESA framebuffer has weird colours
(from the very start) but the X server runs fine (it locks up from
time to time but that happens on other systems as well so it's
probably unrelated to not having a BIOS). Also the X server would not
run without agp driver at least (unless I would run on top of the
broken VESA fb).

Speaking of removable devices .. it seems that the CD-rom if inserted
becomes hd0 which breaks my grub config.

Thanks

Michal