grub2 in fedora 22

[Patrick Dupre]

Hello,

I had a bad surprise.
After the last update grub2-mkconfig -o /boot/grub2/grub.cfg
the grub.cfg is not correct
I have:

menuentry 'Fedora (4.1.2-200.fc22.i686+PAE) 22 (Twenty Two)' --class fedora --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-4.1.2-200.fc22.i686+PAE-advanced-78c1373b-43b8-4706-8771-4bc5a2ea0fa4' {
    set gfxpayload=text
    insmod gzio
    insmod part_msdos
    insmod ext2
    set root='hd0,msdos6'
    if [ x$feature_platform_search_hint = xy ]; then
      search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos6 --hint-efi=hd0,msdos6 --hint-baremetal=ahci0,msdos6 --hint='hd0,msdos6'  fff6282e-eb24-405f-b43b-06ba5cc92c70
    else
      search --no-floppy --fs-uuid --set=root fff6282e-eb24-405f-b43b-06ba5cc92c70
    fi
    linux16 /vmlinuz-4.1.2-200.fc22.i686+PAE root=/dev/mapper/VolGrpSys0-root ro vconsole.keymap=fr rd.dm=0  rd.md=0 rd.luks=0 vconsole.font=latarcyrheb-sun16 rd.lvm.lv=VolGrpSys3/root 
    initrd16 /initramfs-4.1.2-200.fc22.i686+PAE.img
}

while it should be:

inux16 /vmlinuz-4.1.2-200.fc22.i686+PAE root=/dev/mapper/VolGrpSys0-root ro vconsole.keymap=fr rd.dm=0  rd.md=0 rd.luks=0 vconsole.font=latarcyrheb-sun16 rd.lvm.lv=VolGrpSys0/root

VolGrpSys0/root is a fedora 20.

where did grub2-mkconfig find this wrong information?
How can I fix it (i.e. not manually in gbub.cfg

Thank.

===========================================================================
 Patrick DUPRÉ                                 | | email: [e-mail]
 Laboratoire de Physico-Chimie de l'Atmosphère | |
 Université du Littoral-Côte d'Opale           | |
 Tel.  (33)-(0)3 28 23 76 12                   | | Fax: [phone]
 189A, avenue Maurice Schumann                 | | 59140 Dunkerque, France
===========================================================================

[Chris Murphy]

Two things to check. Make sure the fstab on both are correct because
grub2-mkconfig depends on both fstabs to build the grub.cfg.

Next would be to add line GRUB_DISABLE_OS_PROBER="true" in the
/etc/default/grub and the it will only make a grub.cfg for Fedora 22
and you can see if that's correct. If it's still not correct, but
fstab is correct, then I'm lost, maybe it's a bug.

If that fixes it, but you want a Fedora 20 entry in the Fedora 22 GRUB
menu, then I recommend editing /etc/grub.d/40_custom to add a menu
entry that searches for the F20 boot volume and uses configfile
command to point to the Fedora 20 grub.cfg. If you post a Fedora 20
menuentry it's easier to give an idea what this looks like. Mine looks
like this:

### Created by me ###
{
set root='hd0,gpt7'
search --no-floppy --fs-uuid --set=root c9f73a53-7d83-4ead-991a-c445d7c3e5d9
configfile /boot/grub2/grub.cfg
}

But it's very simple, because it's a UEFI example so there's not need
to load LVM or file system modules because that's handled by the
firmware instead of GRUB, but you get the idea.

Chris Murphy