[lfs-dev] grub-2.02~beta2

Dan McGhee beesnees at grm.net
Fri Oct 3 15:06:10 PDT 2014


On 10/03/2014 03:47 PM, Bruce Dubbs wrote:
> Craig Magee wrote:
>> On 3 October 2014 22:10, Mattias Schlenker <ms at mattiasschlenker.de> 
>> wrote:
>>
>>>
>>> On UEFI you could do the same: Add LFS to an existing GRUB. On the 
>>> other
>>> hand you could add an GRUBX64.EFI as LFSX64.EFI to the list of UEFI
>>> bootloaders via efibootmgr. On a fresh machine with just LFS and no 
>>> other
>>> systems you would probably use the default /EFI/BOOT/BOOTX64.EFI.
>>>
>>> In my opinion this is to much complexity. Thus I would recommend not
>>> creating partitions for LFS, but in any case use a separate drive. This
>>> might even be a 32GB USB thumb drive (should cost less than 15€), do a
>>> clean install (thus not thinking about dual boot configurations).
>>
>>
>> That is what I did recently.  I built 64-bit LFS in a folder on my
>> fileserver (a Core Duo running Debian stable), then copied it to a USB
>> stick.  I created two GPT partitions, one FAT32, one EXT2.  By compiling
>> the kernel with a built-in command of root=PARTUUUID=(Id of EXT2 
>> partition)
>> and placing it in /boot/BOOT/BOOTX64.EFI I now have a USB stick that 
>> boots
>> on my Asus laptop and Mac by bringing up the boot options menu.
>> There's no specific reason to use GPT.  My goal is to create a hybrid 
>> table
>> I can install GRUB2 to with efiemu to see if I can get the stick to 
>> boot on
>> older non-GPT aware BIOS systems.  I don't know if that's a realistic 
>> goal,
>> the fun part is finding out!
>
>> I find EFI to be okay for booting my system with as EFI entries can pass
>> arguments to the kernel and boot it directly without GRUB.  I don't use
>> Windows so don't have any issues with it.  GPT seems to be the 
>> inevitable
>> future though, and is pretty darn neat.
>
> A GPT partition table with a legacy BIOS is OK.
> A MBR partition table with URFI is not OK.
>
> Secure boot and UEFI are not synonymous.  If you don't use windows, 
> the easiest way is to just disable secure boot.

Just one "tweak" to your statement.  "Secure Boot" has nothing to do 
with running windows.  If you turn off secure boot, then you can make 
the OS Boot Manager use any boot loader you chose. If I recall what you 
did do your system, you re-formatted the hard drive and then installed 
grub to your "boot" partition.  You can do essentially the same thing by 
"enabling BIOS Mode."  Then you can use the PMBR layer--in essence your 
boot partition--to install grub or lilo or any other boot loader.  In 
EFI Mode, you use the EFI partition as what the LFS book calls the "boot 
partition."  There *should* be an option in your BIOS settings to do 
something like this.

Secure Boot merely has the OS boot manager look in the EFI variables for 
"signed" keys and limits the boot loader selection to only those with 
these keys--which microsoft controls.

In my research, I have encountered what I call "problems" because UEFI 
firmware is still so  manufacturer-dependent.  There's no common jargon 
yet.  BIOS Mode, Legacy Mode, BIOS Legacy Mode are all synonymous.  It 
can get quite confusing.

There's some great info that explains all of this in almost excruciating 
detail here:

http://www.rodsbooks.com/efi-bootloaders/index.html

Rod Smith, the author of the documents on the link, is the developer and 
maintainer of rEFInd.  Although I don't know specific dates, I have a 
hunch that the stuff at his website was written before grub-2.02~beta2 
got put in its final format.

I'm going to stop here.  I could go on for awhile, but that would make 
this excruciatingly long.  My intent was only to amplify the remarks 
about "Secure Boot."

Dan





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