[kwlug-disc] Linux on Windows 8 laptops with UEFI

[Khalid Baheyeldin]

No, I did not turn anything off.

I just told UEFI that I want to boot from DVD (or was that: "boot first
from DVD, then hard disk", don't know), and things just worked as expected.

I think what is happening is that a) Ubuntu is one of the recognized
vendors whose secure boot keys are accepted and b) it stores the keys in
/boot/efi.

The stuff in boot/efi/EFI/ubuntu is as follows:

# ls -l /boot/efi/EFI/ubuntu/
total 2104
-rwxr-xr-x 1 root root     115 Apr  9 17:47 grub.cfg
-rwxr-xr-x 1 root root  793464 Apr  9 17:47 grubx64.efi
-rwxr-xr-x 1 root root 1355736 Apr  9 17:47 shimx64.efi

And ...

# file /boot/efi/EFI/ubuntu/*
/boot/efi/EFI/ubuntu/grub.cfg:    ASCII text
/boot/efi/EFI/ubuntu/grubx64.efi: PE32+ executable (EFI application) x86-64
(stripped to external PDB), for MS Windows
/boot/efi/EFI/ubuntu/shimx64.efi: PE32+ executable (EFI application) x86-64
(stripped to external PDB), for MS Windows

Note the "for MS Windows" part!

And ...

# cat /boot/efi/EFI/ubuntu/grub.cfg
search.fs_uuid 82cef56a-blahblah root
set prefix=($root)/boot/grub
configfile $prefix/grub.cfg

So, it seems to me that this stuff will remain static across kernel
upgrades, and that is how they keep secureboot and UEFI happy, while
keeping the kernel customizable to all geeky whims.

Mind you, I have not tried a PC/Laptop with dual boot, but it seems that
secureboot and UEFI are OK if you use Ubuntu (and a few other distros).


On Wed, Apr 9, 2014 at 6:51 PM, unsolicited <unsolicited at swiz.ca> wrote:

> Interesting.
>
> So you had to turn of SecureBoot to boot the DVD? Or just changed the boot
> order?
>
> If turn off of SecureBoot, did turning it on post-install still let it
> boot?
>
> Evidently, note to selves, don't nuke the /boot/efi partition? (In which
> Ubuntu is probably putting keys for the UEFI / SecureBoot to find at
> startup? [Or turn off SecureBoot and live with it that way if you don't
> want the extra partition?]
>
>
>
> On 14-04-09 03:51 PM, Khalid Baheyeldin wrote:
>
>> A followup on this thread.
>>
>> I had to replace a PC that is running Linux exclusively, with a new one.
>>
>> The new one had UEFI and Windows 8.
>>
>> For this PC, I don't need Windows at all, so I just inserted the Ubuntu
>> Server 12.04.4 LTS DVD and did a normal install from it, changed the UEFI
>> to boot from the DVD, and all went smoothly. Nothing special at all.
>>
>> The only difference from old BIOS PCs is that there is a partition that is
>> mounted at /boot/efi and contains a directory named EFI with a directory
>> named ubuntu under that.
>>
>> So, as mentioned in this thread before, nothing much if you have Linux on
>> its own.
>>
>>
>>
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>>
>
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-- 
Khalid M. Baheyeldin
2bits.com, Inc.
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