Grub is not backwards compatible
FedoraForum.org - Fedora Support Forums and Community
Results 1 to 7 of 7
  1. #1
    Join Date
    Jun 2005
    Location
    Montreal, Que, Canada
    Posts
    5,488
    Linux (Fedora) Firefox 63.0

    Grub is not backwards compatible

    My main distribution is fedora 28, and will be until I am able to install a printer with Fedora 29. I have Fedora29 on my /dev/sdc. I can boot from it and the grub therein shows all the other "grub configs".
    But from Fedora28, it does not show the Fedora29 versions.

    Anyone else note this situation?
    Leslie in Montreal

    Interesting web sites list
    http://forums.fedoraforum.org/showth...40#post1697840

  2. #2
    Join Date
    Nov 2016
    Location
    Germany
    Posts
    37
    Linux Firefox 60.0

    Re: Grub is not backwards compatible

    Do you have a UEFI installation?

    I don't use grub from Fedora since long.
    os-prober does not create the stanza to boot Fedora on UEFI installations. I create it manually via /etc/grub.d/40_custom.

  3. #3
    Join Date
    Jun 2005
    Location
    Montreal, Que, Canada
    Posts
    5,488
    Linux (Fedora) Firefox 63.0

    Re: Grub is not backwards compatible

    No,
    I did the following.
    from the sdc F29 version,
    sudo grub2-install /dev/sdc # to create a biosboot
    sudo grub2-mkconfig -o /boot/grub2/grub.cfg

    From the F28 system (on /dev/sda)
    sudo grub2-mkconfig -o /boot/grub2/grub.cfg
    the latter grub.cfg lists the F29 version, but
    pointers are wrong and do not correctly connect to grub on the F29

    No backwards compatibilty
    Last edited by lsatenstein; 3rd November 2018 at 05:53 PM.
    Leslie in Montreal

    Interesting web sites list
    http://forums.fedoraforum.org/showth...40#post1697840

  4. #4
    Join Date
    Nov 2016
    Location
    Germany
    Posts
    37
    Linux Firefox 60.0

    Re: Grub is not backwards compatible

    For a long time member you gave very little information. Cross booting between disks is also a special case.

    To prove that there is no backwards compatibility you'll have to

    i) give the version numbers of grub and os-prober
    ii) pass through the same steps, i.e. invoke # grub2-install also in Fedora 28.

    It should not boot grub on F29 (chainloading) but the kernel.

    Greetings
    Bequimão

  5. #5
    Join Date
    Jun 2005
    Location
    Montreal, Que, Canada
    Posts
    5,488
    Linux (Fedora) Firefox 63.0

    Re: Grub is not backwards compatible

    By the way...
    Grub on /dev/sda works with the grub from Manjaro, Tumbleweed, and other F28 KDE Fedora version. I have it working now with a F29 Remix that does not use the newer grub.

    One main menu lists my 5 distros. (F28Gnome,F28KDE,Tumbleweed(common KDE and Gnome), F29KDE (test), F29Gnome(test).
    I want to upgrade F28 to F29, but I can't install my printer with F29 Gnome, whereas this printer is on the other mentioned distros
    The Gnome Remix grub is recognized by the F28 version. F29 introduced some new features that make it incompatible with the previous version.
    Leslie in Montreal

    Interesting web sites list
    http://forums.fedoraforum.org/showth...40#post1697840

  6. #6
    Join Date
    Aug 2007
    Posts
    298
    Linux Firefox 52.0

    Re: Grub is not backwards compatible

    From the F28 system (on /dev/sda)
    sudo grub2-mkconfig -o /boot/grub2/grub.cfg
    the latter grub.cfg lists the F29 version, but
    pointers are wrong and do not correctly connect to grub on the F29
    Could you please post what you mean by "pointers are wrong" ? Place the appropriate sections of the F28 grub.cfg presumably generated by os-prober which refer to the F29 installation in a code box for us to examine.

    Also the title of your post is wrong. This is forward compatibility and not "backward compatibility". If you are trying to control a newer F29 grub with an older F28 grub this is forward.

    I have Fedora29 on my /dev/sdc. I can boot from it and the grub therein shows all the other "grub configs".
    This means that the newer F29 grub is backward compatible with earlier grub releases.

    It is best to do this with entries you put in /etc/grub.d/40_custom. You can either load the core.img of the F29 grub or load its config file. If the F29 grub version is newer it is best to load its core.img so the newer version takes control.

    Code:
    menuentry 'Fedora 24 using grub2 configfile' {
       insmod ext2
       insmod part_gpt
       search --no-floppy --set=root --label boot_fedora24
       configfile /grub2/grub.cfg
    }
    
    menuentry 'Fedora 24 using core.img chainloading' {
       insmod ext2
       insmod part_gpt
       search --no-floppy --set=root --label boot_fedora24
       multiboot /grub2/i386-pc/core.img
    }
    Last edited by amiga; 9th November 2018 at 10:13 PM.

  7. #7
    Join Date
    Aug 2007
    Posts
    298
    Linux Firefox 52.0

    Re: Grub is not backwards compatible

    Cross booting between disks is also a special case.
    Actually if you search by either UUIDs or file system labels it does not matter if it is across disks.

    It should not boot grub on F29 (chainloading) but the kernel.
    If the grub version is newer with F29 core.img 'chainloading' by loading the newer grub's core.img file is the recommended approach as stated by the grub manual. In a multi-boot system the newest grub version should control the system as its is (proper usage of the term) backwards compatible with older grub versions.

    From the grub2 manual

    Code:
    menuentry "experimental GRUB" {
              search --set=root --label GRUB --hint hd0,msdos5
              multiboot /experimental/grub/i386-pc/core.img
    }
    Last edited by amiga; 8th November 2018 at 11:00 PM.

Similar Threads

  1. Grub 2 - non compatible video card/settings
    By qbic2005 in forum Using Fedora
    Replies: 1
    Last Post: 21st February 2012, 08:11 PM
  2. Counting Backwards to F15
    By steelaworkn in forum Reviews, Rants & Things That Make You Scream
    Replies: 0
    Last Post: 12th December 2011, 05:51 AM
  3. KDE 4 - step backwards?
    By martin.sourada in forum Fedora Focus
    Replies: 16
    Last Post: 23rd April 2008, 02:33 AM
  4. Going backwards on Firefox
    By xathrasmurphy in forum Hardware & Laptops
    Replies: 2
    Last Post: 19th January 2005, 10:09 PM
  5. I am backwards
    By IceNine in forum Linux Chat
    Replies: 12
    Last Post: 28th October 2004, 09:21 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •