• Cnchi to allow to enter the "grub>" prompt?


    Hi @developers!

    Could allow chchi installer to present as one of the initial choices to enter to the “grub>” prompt?

    That would be helpful in cases when the system will not boot anymore, since the system could be made to boot with just a couple of very simple commands, even without chroot (which is confusing to many people).

    These commands could be given under the “grub>” prompt:

    search.file /etc/pacman.d/antergos-mirrorlist root
    configfile /boot/grub/grub.cfg
    

    and it then boots to Antergos again, and then fixing the boot issues would be much easier.

  • @manuel said in Cnchi to allow to enter the "grub>" prompt?:

    Could allow chchi installer to present as one of the initial choices to enter to the “grub>” prompt?

    i do not understand what you want provide here fully…

    As cnchi is not starting from grub…

  • @joekamprad
    If an installed system is no more booting for example after an update, then it would be nice if cnchi could provide booting to the “grub>” prompt. Many other distros offer that option in their installer.

    In “grub>” prompt it would then be easy to give the above commands to boot to the installed system without using chroot. And then fix the system if possible.

    Of course booting to the system can be done using installer’s arch-chroot, but that is an extra step, and many newcomers can have a problem with that.

    As you can see, this is not the highest priority thing to do. I was just wondering if there is a simple way to provide that in cnchi. If it not easy, then this has a lower priority than many other things in the Antergos development TODO list.

  • @manuel said in Cnchi to allow to enter the "grub>" prompt?:

    cnchi

    is only the installer backend, what is running to install system inside Live Iso session… it can not be started out of grub without a running graphical session.

    What you want to say is to have a boot menu entry trhat boots into CLI and not into the graphical system?

  • @joekamprad
    No. But cnchi probably is not the right program here, you’re right.

    I mean the first page that shows when booting with the installer USB stick, it gives you a simple menu of

    • booting to the hard drive (the installed system)
    • booting the live installer
    • the third thing I now don’t remember as I can’t really check it

    On the same first page there’s also function keys F1…F4 below for configuring some stuff like video resolution, language, kernels, etc…

    On that page you could have an additional entry, to go to the “grub>” prompt. That prompt is sometimes shown on booting error situations.

  • @joekamprad said in Cnchi to allow to enter the "grub>" prompt?:

    i do not understand what you want provide here fully

    @manuel wants cnchi to add an extra entry to grub to make easies to fix the system. It automatically add Antergos etc.

    Just for example: Portergos adds a terminal boot option at grub, and next version will offer the user to boot Portergos iso too, so in case graphical login errors or other the user can use terminal login or boot the iso.

    I wasn’t aware of these command from @manuel, i’ll certainly give it a shot here.
    How should be the menuentry?

  • all this boot entries are not generated by a skript, they are “hardcoded” and used as they are written.

  • @joekamprad
    Yes, this seems to be what I meant, isolinux entries and efiboot loader entries. Sorry about my ignorance about those, I’ve never really needed to work with them.

    So there should be an entry for starting the “grub command shell” (https://wiki.archlinux.org/index.php/GRUB#Using_the_command_shell).
    I really don’t know how to start that, I was hoping someone else does.

    But and if that can be started, then the commands above could be used for booting the system (if it is still possible).

  • @fernandomaroto
    The commands above just try to “chain” to the actual grub.cfg of the installed system, and thus allow boot from it. No additional menuentry is needed.

    For example, if on a legacy boot system the MBR has been corrupted and booting the system is impossible, then this way we can use the installer stick to “provide the MBR” (allow the boot) and start normal boot of the installed system using its grub.cfg.

    And I’d also like to test that the custom.cfg (in addition to grub.cfg) can be used for booting this way. ;)

  • i do not know if it is possible to get into grub shell by a menu entry… as it will go there automatic on some cases, but not all fails…

  • @joekamprad
    OK, I try to find how to start it, or is there any other useful workaround.

    Thanks guys for participation and ideas. :)

  • @joekamprad said in Cnchi to allow to enter the "grub>" prompt?:

    all this boot entries are not generated by a skript, they are “hardcoded” and used as they are written.

    Ok, you’re talking about the iso image which uses syslinux.

    I understood you were talking about grub entries, and thining about addind an entry there, like using /boot/grub/custom.cfg (that is booting from hard disk, not the iso)

    Now thinking about it a litle more, i’m think it’s possible to do with both of them (syslinux and GRUB).

    I admit i haven’t tested though.

  • yes i was first thinking @manuel was talking about adding this to the installed system, but he clearify to add this to iso… what is different then also as it uses syslinux / gfsxboot from suse linux ? and efiboot is also something different…

  • I’m lost again here:
    If the HD is not booting due to some GRUB error, why try to boot it redirecting from ISO? Wouldn’t the user find the same error? (i think after redirenction the booting process will stop at corrupted GRUB and not boot the system directly)

    Are you trying to boot the system jumping the grub step? Don’t know if it’s possible, that would be very nice though.

    Also Antergos and Arch based distros already have an option to boot HD directly from syslinux menu. The menu entry is present at syslinux.cfg file and it’s like bellow:

    LABEL hdt
            MENU LABEL HDT (Hardware Detection Tool)
            COM32 hdt.c32
    

    If i’m not mistaken hdt.c32 file is binary, and i have no idea how to play with it in case you want to find a way to detect hardware and boot differently.

  • When booting to an installed system, you can give ‘c’ in grub to load the grub shell mode. This mode is what I’m talking about.

    But seems that this can be done only after being already in grub, and the installer stick is booting with syslinux. So the installer is no grub. How can this barrier be crossed?

    I also found this link about the grub command shell:
    https://www.linux.com/learn/how-rescue-non-booting-grub-2-linux

    Seems that loading module normal.mod starts the grub command shell if I understand it right. If that is the case, can that be done by the installer?

  • @manuel
    maybe try to call GRUB from syslinux (since grub is installed in the .iso)
    https://duckduckgo.com/?q=call+grub+from+syslinux

  • @fernandomaroto
    That idea might work, but I don’t see grub in the Antergos ISO…
    By the way, is grub installed into Portergos ISO?

  • I looked at the Portergos ISO, and didn’t find grub there either…

cnchi154 grub111 allow5 enter4 Posts 26Views 868
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