Mountpoint for the ESP

sMueggli · Guru Joined: 03 Sep 2022 Posts: 493

Please do not confuse efibootmgr with an EFI binary such as rEFInd.

From "man 8 efibootmgr":

pietinger · Posted: Sun Sep 24, 2023 1:29 pm Post subject:

sMueggli,

I completely agree with your post. Thank you very much !

P.S.: Yesterday and today I have updated these Wiki articles:

https://wiki.gentoo.org/wiki/EFI_System_Partition
https://wiki.gentoo.org/wiki/Efibootmgr
https://wiki.gentoo.org/wiki/EFI_stub

Still not updated is our article about grub:
https://wiki.gentoo.org/wiki/GRUB

(and maybe some other articles having a reference to the mountpoint of the ESP)

De-Javu · n00b Joined: 30 Mar 2009 Posts: 24 Location: USA

pietinger · Posted: Sun Sep 24, 2023 8:58 pm Post subject:

I have not updated https://wiki.gentoo.org/wiki/GRUB because it is too complicated for me (too many translation tags; I dont know how to handle). The same is true for https://wiki.gentoo.org/wiki/Systemd/systemd-boot

But I encourage all wiki editors to make these pages. You help not only our chief wiki editor @maffblaster but all readers.

Goverp · Advocate Joined: 07 Mar 2007 Posts: 2179

szatox · Advocate Joined: 27 Aug 2013 Posts: 3430

Goverp: From efi's (and efibootmgr's ) point if view, booting into refind is no different than booting into a stub kernel or anything else.
It is not a different function.

Seriously, the whole thing feels like a gimmick; there was nothing wrong with the old way of preparing motherboard to boot (setting boot device in BIOS, like we used to before efi became all the rage), and - IF you use an on-disk bootloader, like almost everyone - there is no point in changing this old way.
Saving you a single reboot by setting vars from within the OS is hardly an improvement, and definitely not worth all the confusion there is around managing EFI "the right way", demonstrated by last 2 pages worth of posts in this thread.

GDH-gentoo · Posted: Mon Sep 25, 2023 12:42 pm Post subject:

pjp · Administrator Joined: 16 Apr 2002 Posts: 20485

GDH-gentoo · Posted: Wed Sep 27, 2023 3:26 pm Post subject: Re: Mountpoint for the ESP

pjp · Administrator Joined: 16 Apr 2002 Posts: 20485

I didn't read 3 because everyone knows that's "profit." :)

As I only have the "backup" .efi file (bootx64.efi), I suppose efibootmgr must have installed it.

Hopefully RISC-V doesn't require UEFI.
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Quis separabit? Quo animo?

Anon-E-moose · Posted: Wed Sep 27, 2023 6:26 pm Post subject:

Nothing really complicated about uefi.

I have the driver for gummiboot loader,
then per kernel, I have vmlinuz and the system map, from the compile,
and a small text file to go with it.

pietinger · Posted: Wed Sep 27, 2023 6:30 pm Post subject:

pjp · Administrator Joined: 16 Apr 2002 Posts: 20485

GDH-gentoo · Posted: Wed Sep 27, 2023 10:51 pm Post subject:

pjp · Administrator Joined: 16 Apr 2002 Posts: 20485

Thanks. That would seem to indicate I had to have done something for /boot/EFI/BOOT/boox64.efi to exist.
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pietinger · Posted: Thu Sep 28, 2023 2:33 am Post subject:

In this post I gave two links for UEFI and CSM booting:
https://forums.gentoo.org/viewtopic-p-8802471.html#8802471
(I have alos gave a list what you will need for an UEFI boot)

pjp,

if you buy a new computer there is usually a windows installed. Therefore there is an UEFI boot entry pointing to the start programm in \efi\microsoft\...

What happens if the BIOS loses its information (empty BIOS battery; reset by User) ? If now a windows user would power on this computer, the BIOS would tell that there is no OperatingSystem ... and the windows user then gets a heart attack.

In order to protect the user from this heart attack, some manufacturers have additionally added an "emergency system programm". It was copied onto the harddisk into the ESP of the harddisk in the directory \efi\boot and was named bootx64.efi.

bootx64.efi is a name every UEFI BIOS must recognize without having an boot entry in its table ... it is "hardcoded" into UEFI. If UEFI has no EXPLICIT entry to an EXISTANT boot-file then it will ALWAYS search for this name ... Necessary for booting from a removable(*) medium, like a USB stick (because you want not create an extra boot entry only to be able to boot from a stick). This name can be used also for a file on your harddisk.

(* --removable is also the NAME of a parameter for grub-install ... because this is the sense)

Back to Windows:

As long as your UEFI have an entry pointing to MicrosoftWindows it will boot Windows. Two ways to lose it:

a) If your harddisk gets broken and cannot boot Windows anymore, THEN there is still an UEFI entry, but UEFI cannoot load (and start) the Windows-binary ... so, UEFI tries to start the "hardcoded" bootx64-file.

(Also UEFI will delete this entry in its table because for UEFI it is not a functional entry)

b) If BIOS looses the entry because of a reset, it tries also to start the "hardcoded" bootx64-file

If you build your system with a new mainboard and a new harddisk, then you will have no "emergency application" from a mnaufacturer. You will have no bootx64.efi ... nothing ... empty harddisk. You boot now a Linux from a stick or a CD-ROM and this will install ... something ... but USUALLY NOT a bootx64.efi file. For example: grub will install you a \efi\gentoo\grubx64.efi (I dont know what refind installs).

Now we have one exception with grub: Because there exists some old mainboards with a "bad" UEFI BIOS - NOT accepting a new UEFI boot entry - grub-install ALLOWS you, to install (the first part of) grub AS bootx64.efi (instead grubx64.efi). If you never use the parm --removable you will never have a bootx64.efi on your harddisk ... I also dont have it, because I have build my system too.

pjp · Administrator Joined: 16 Apr 2002 Posts: 20485

pietinger · Posted: Thu Sep 28, 2023 10:05 am Post subject:

pjp · Administrator Joined: 16 Apr 2002 Posts: 20485

pietinger · Posted: Sun Oct 01, 2023 8:23 am Post subject: