[uds-announce] Dual Boot Installation with Ubuntu

[Steve Riley]

On 2012-10-31 20:27:18 Göran Gustafsson <gustafsson.g at gmail.com> wrote:
>
> Yes, Apple doesn't fully follow the specs. I've read that they use a mix of
> version 1 and 2.
> 
> From my experience you can only boot if the file is named
> EFI/boot/bootx64.efi. Otherwise you can't see the option when holding down
> the option key at boot.

>From my experience with UEFI, I've found that the only image the firmware will 
load without a corresponding NVRAM variable is whatever happens to be named 
EFI/boot/bootx64.efi. To boot other images, an NVRAM boot variable is required, 
and this variable typically points to the GRUB boot loader. When you have the 
variable defined, it'll show up in the boot manager menu when you press the 
interrupt key.

Normally, GRUB will run efibootmgr and set this up for you automatically. You 
can examine what's in your NVRAM variables with

sudo efibootmgr -v

Lately, I've begun removing GRUB and configuring my firmware to directly boot 
vmlinuz. I like this, but I have to manually copy the kernel image to 
EFI/boot/ubuntu each time there's an upgrade. Happy to show folks how this 
works on my ThinkPad X1, which I have with me here at UDS.

...Steve