zapped boot info

[blind Pete]

Wes James wrote:

> On Fri, May 9, 2014 at 5:23 AM, blind Pete <0123peter at gmail.com> wrote:
> 
>> Wes James wrote:
>>
>> > I have a mac pro (2010?) that is set up with xubuntu 12.04.  The first
>> > disk in the system has windows, the second has os X and xubuntu / and
>> swap
>> > partitions.  The user upgraded to maveriks, but now when the system
>> > start
>> > you can see Windows, Xubuntu and OS X in the refit boot menu.  When you
>> > select Xubuntu, it boots in to windows.
>>
>> Disappointing.
>>
>> > I booted from the super grub disk
>> > ( http://www.supergrubdisk.org/ ) and can select the Xubuntu option and
>> it
>> > boots fine.  I've looked in gparted to see where the boot loader might
>> > have been for xubuntu, but I can't tell.
>>
>> Can you tell how many partitions there are?  Look for a "fat" partition,
>> on either disk.  Also, "sudo blkid" will list your partitions.
>> Do you have anything under </boot/efi/> ?
>>
>> > There is a /boot folder so I think the
>> > system was partitioned in to / and swap only.  Any suggestions on
>> > getting
>> > xubuntu booting again.  I've tried update-grub2, but that doesn't help.
>> >  I've looked at using the grub-install, but I'm not sure what
>> >  parameters
>> > I'd use to run it.  I tried:
>> >
>> > sudo grub-install /dev/sda
>> >
>> > but it says it can't do that on a GPT partition. Same with /dev/sdb.
>> >
>> > Thanks,
>> >
>> > -wes
>>
>> One way to get the right answer on usenet is to start by posting
>> the wrong answer...
>>
>> Re-install from scratch, just like Windows.
>>
>> ;-)
>>
> 
> I've been thinking about reinstalling, but what is the difference between
> reinstalling and running grub-install. 

Grub-install would be one of the things that gets done during a full 
install, I can not be relied upon to list all of the things that 
happen during a full install.  

> This version has /boot as just a
> folder under / as it was set up with / and swap during intall.  

On some systems having a separate partition for /boot is 
significant.  What I am interested in is, is there a separate 
/boot/efi partition?  Confusingly the computer's firmware will 
want a small "fat" partition for the boot process, but it only 
needs on for the hardware, and it might not be mounted by 
all (or any) of the operating systems installed.  

> I can try
> it again.  It is /dev/sdb4 on the disk so should I be able to do
> grub-install --boot-directory=/mnt/boot /dev/sdb4 from a live cd???

Grub2 does some things that I do not understand, especially on efi 
computers.  

> thanks,
> 
> -wes

-- 
blind Pete
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