Re: Is UEFI/GPT difficult
Posted: Mon Feb 25, 2019 2:46 am
Brian K wrote:
> Bruce,
>
> I assume you are using BIU. For each Linux install select the ESP in the
> "Device for boot loader installation" field.
>
> Each Linux install will create its own folder in the ESP. For example, if
> you installed Mint Cinnamon, Ubuntu and Fedora you would have these folders
> in the ESP. ubuntu.001, ubuntu.002 and fedora.001. Each folder contains
> grub, etc.
>
> Or did you mean something else?
Hi Brian,
OK, I just did a fresh install of Manjaro to ensure I got my explanation straight.
For install, I did the following:
- ensured ESP was recognized, and that boot and EFI flags were ticked.
- ensured the OS partition did not have a boot flag ticked.
The result on reboot is
- BIU was bypassed, and a Manjaro grub installation presented a boot menu.
- on getting into the OS, ESP has had the following folder added /EFI/Manjaro.
- no other folders have been added to ESP
- within /EFI/Manjaro/ is one file = grubx64.efi
So where are the grub program's files installed?
They are installed on the Manjaro OS partition at
/boot/efi/grub/
There are three folders
/fonts/
/themes/
/x86_64-efi/
and 2 files in the main folder
grub.cfg
grubenv
So in this setup, Manjaro has been registered with UEFI as the default system to boot.
So on bootup, UEFI passes control to
ESP at /EFI/Manjaro/grubx64.efi
This file passes control to grub which displays the boot menu.
And selecting the Manjaro option passes control to the Manjaro kernel with its integrated boot stub.
The kernel file in this case is
/boot/vmlinuz-4.19-x86_64
--------------------------------------------------------
OK, that's a pretty clear explanation of a reasonably clear Linux installation.
Grub can be reinstalled and updated, and the only thing that will change on ESP is /EFI/Manjaro/grubx64.efi
However, some Linux distros install the grub program in its entirety on ESP under a folder called /EFI/grub/....other distros install selected grub program files on ESP under /EFI/ubuntuxxx/
My question relates to this variation between Linux OSs in what folders/files they place in ESP.
This is especially pertinent when one starts running clones of the same Linux OS.
Because a clone OS will need its own install of the grub program in addition to its own folder i.e. ESP /EFI/ubuntu.00x+1
THis is important so as to keep independent installs of grub program for each incidence of an OS especially when there's an original OS and a clone of it.
---------------------------------------------------
These variations in what each OS installation does on ESP are why I think a boot menu program such as BIU would be simpler if it probed for Linux OS kernel files and made boot menu items for these. This bypasses the confusion generated when using grub as an intermediary, especially so when booting from original and clone OSs.
> Bruce,
>
> I assume you are using BIU. For each Linux install select the ESP in the
> "Device for boot loader installation" field.
>
> Each Linux install will create its own folder in the ESP. For example, if
> you installed Mint Cinnamon, Ubuntu and Fedora you would have these folders
> in the ESP. ubuntu.001, ubuntu.002 and fedora.001. Each folder contains
> grub, etc.
>
> Or did you mean something else?
Hi Brian,
OK, I just did a fresh install of Manjaro to ensure I got my explanation straight.
For install, I did the following:
- ensured ESP was recognized, and that boot and EFI flags were ticked.
- ensured the OS partition did not have a boot flag ticked.
The result on reboot is
- BIU was bypassed, and a Manjaro grub installation presented a boot menu.
- on getting into the OS, ESP has had the following folder added /EFI/Manjaro.
- no other folders have been added to ESP
- within /EFI/Manjaro/ is one file = grubx64.efi
So where are the grub program's files installed?
They are installed on the Manjaro OS partition at
/boot/efi/grub/
There are three folders
/fonts/
/themes/
/x86_64-efi/
and 2 files in the main folder
grub.cfg
grubenv
So in this setup, Manjaro has been registered with UEFI as the default system to boot.
So on bootup, UEFI passes control to
ESP at /EFI/Manjaro/grubx64.efi
This file passes control to grub which displays the boot menu.
And selecting the Manjaro option passes control to the Manjaro kernel with its integrated boot stub.
The kernel file in this case is
/boot/vmlinuz-4.19-x86_64
--------------------------------------------------------
OK, that's a pretty clear explanation of a reasonably clear Linux installation.
Grub can be reinstalled and updated, and the only thing that will change on ESP is /EFI/Manjaro/grubx64.efi
However, some Linux distros install the grub program in its entirety on ESP under a folder called /EFI/grub/....other distros install selected grub program files on ESP under /EFI/ubuntuxxx/
My question relates to this variation between Linux OSs in what folders/files they place in ESP.
This is especially pertinent when one starts running clones of the same Linux OS.
Because a clone OS will need its own install of the grub program in addition to its own folder i.e. ESP /EFI/ubuntu.00x+1
THis is important so as to keep independent installs of grub program for each incidence of an OS especially when there's an original OS and a clone of it.
---------------------------------------------------
These variations in what each OS installation does on ESP are why I think a boot menu program such as BIU would be simpler if it probed for Linux OS kernel files and made boot menu items for these. This bypasses the confusion generated when using grub as an intermediary, especially so when booting from original and clone OSs.