Is UEFI/GPT difficult

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Re: Is UEFI/GPT difficult

Postby Bob Coleman » Sun Mar 03, 2019 12:22 pm

Brian K wrote:
> Bob,
>
> I just installed BIU to a 5 year old computer and saw issues similar to the
> ones you described. BIU wasn't in Boot Priorities until it was installed
> twice. The USB mouse didn't work in BIU. "Current" was
> temporarily in the Boot Priorities and it didn't boot BIU. I couldn't get
> rid of unwanted items in Boot Priorities. They would Disable but would
> reappear after the next boot.
>
> Now, apart from the mouse, BIU does work. It's an old computer and it will
> be going back into storage. It certainly looks like you need recent UEFI
> Firmware.

Interesting. There is a "PC BIOS Update" available from HP, but I have no reason to believe it has anything with this issue and am not sure I care to risk installing it.
Bob Coleman
 
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Re: Is UEFI/GPT difficult

Postby TeraByte Support » Mon Mar 04, 2019 12:04 am

You can choose to boot any file you want, provided it's an UEFI executable.

UEFI spec requires a ESP.





TeraByte Support
 
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Re: Is UEFI/GPT difficult

Postby brucebne » Mon Mar 04, 2019 8:28 am

TeraByte Support wrote:
> You can choose to boot any file you want, provided it's an UEFI
> executable.
>
> UEFI spec requires a ESP.

UEFI spec requires an ESP folder for windows, mac, and boot managers, like BootIt.
But not for Linux OS.

A boot manager passes control to a boot loader.
Linux kernel files such as vmlinuz-4.19-x86_64, have a built in boot loader (boot stub).

So a boot manager like BIU, installed on ESP, can pass control directly to the kernel file's integrated boot loader....
This cuts out the need of each Linux OS to have grub install a folder on ESP, and avoids all the issues that can arise when deleting, restoring, moving Linux OS partitions.
brucebne
 
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Re: Is UEFI/GPT difficult

Postby Brian K » Mon Mar 04, 2019 1:03 pm

Bruce,

Can you delete the ESP and still boot a Linux OS? Or are you using BIU to boot the stub? Can you install a Linux OS to a GPT disk in a computer that doesn't have an ESP? I haven't tried these scenarios.
Brian K
 
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Re: Is UEFI/GPT difficult

Postby brucebne » Mon Mar 04, 2019 7:17 pm

Brian K wrote:
> Bruce,
>
> Can you delete the ESP and still boot a Linux OS? Or are you using BIU to
> boot the stub? Can you install a Linux OS to a GPT disk in a computer that
> doesn't have an ESP? I haven't tried these scenarios.



Brian,

1.
I haven't experimented deleting ESP. I need ESP to install and run a boot manager like BIU or rEFInd, and windows 10.....

2.
No I can't boot the stub with BIU because BIU only recognizes *.efi files as boot loaders.
It doesn't recognize the kernel files as able to boot the system.
So I boot Linux via *.efi files on the Linux partition.... either /boot/grub/x86_64-efi/core.efi or /grub.efi
This way I don't have to worry about ESP folders.

OTOH, rEFInd does recognize kernel files as boot loaders, and makes a boot item entry for i.e.
/boot/vmlinuz-4.20-x86_64
This totally negates the need for grub.

3.
You are asking the same question essentially as 1.
This should be possible because Linux OSs do not need ESP, which is how rEFInd works.
However, in practice, this no doubt depends on UEFI firmware capabilities....and as we both know, these vary significantly.
brucebne
 
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