On Wed, May 22, 2019 at 11:16 AM Kevin Wilson <wkevils@xxxxxxxxx> wrote: > > Hi all, > > I had installed Fedora 30, on a dual boot machine which has a second > partition with Fedora 28. > Fedora 30 comes by default with a new boot loader spec. > > I found under /boot/loader/entries/ the following: > > ls /boot/loader/entries/ > > ec1b8b7719964c8b9a1d8db430c63fd6-0-rescue.conf > ec1b8b7719964c8b9a1d8db430c63fd6-5.0.9-301.fc30.x86_64.conf0 > > I want to be able to boot by default into Fedora 28. There are a couple of ways to do this. I have't tested any of them, so I'm not sure which is the most reliable. On Fedora 28 do you have /usr/sbin/grub2-switch-to-blscfg ? If so, one option is to convert Fedora 28 to use BLS - and then it's possible for Fedora 28 and Fedora 30 to share a single /boot where all the kernels and drop-in bootloader .conf files go. The one tricky thing is, if this is UEFI, we would probably want to make sure Fedora 28 /etc/fstab does not mount the EFI System partition on /boot/efi because we'll want to prevent the older Fedora 28 EFI bootloader packages from overwriting the contents of the EFI system partition. It's fine for the packages to get installed on Fedora 28 though. Another strategy is to edit the Fedora 30 grub.cfg (strictly speaking should using either /etc/grub.d/40_custom or /etc/grub.d/41_custom) so that there is a single "forwarding" entry to Fedora 28's grub menu. That menu entry uses the GRUB 'configfile' command and points to the Fedora 28 grub.cfg. Now Fedora 28 goes on updating its grub.cfg normally. It should be possible to give this forwarding menu entry a proper title that can be set as the saved_entry in the grubenv so that GRUB will use it by default. I know, it seems a little bit Rube Goldberg but at least it'd all be self-describing. Thing is, each strategy does differ on the details depending on firmware type: BIOS or UEFI. On BIOS, the grub.cfg is self contained in the /boot for that particular version of Fedora. Whereas with UEFI, the grub.cfg goes on /boot/efi/EFI/fedora/ no matter the Fedora version, which happens to be on the EFI system partition. So out of the box, two Fedora bootloaders cannot co-exist on UEFI, F28 will always try to step on the grub.cfg there, where F30 never updates it. I'm also not really sure that Fedora 28's GRUB blscfg.mod is getting all the latest updates and bug fixes. It's going EOL in 5 days. > > Is there a way by some utility to generate entries under > /boot/loader/entries/ for the > Fedora 28 and choose Fedora 28 as the default ? Dual Fedoras has never exactly been easy. It requires some esoteric knowledge of GRUB as well as update and upgrade handling to know the path of least resistance. (I say that from a system with six or seven Fedoras on a single Btrfs volume, each in their own subvolume, and if i want to flip to one of the others, I just hand edit the menu entry changin the 'rootflags=subvol=root30' to use root29 or root28 or rootraw or whatever. The gotcha of course is those roots don't necessarily have matching kernel modules for the /boot kernel + initramfs. Since I'm using Fedora 30 95% of the time, I just manually 'cp -a --reflink' copy the latest modules from F30 to the proper location in the rootX subvolume for the Fedora version I want to boot.) The nice thing about BLS going forward is with minimal effort it is possible for Fedora 29, 30, 31 to share a single /boot, they all drop their kernels, initramfs, and matching bls snippets there, and they all appear in the same GRUB menu. The one thing to change is /etc/fstab so older Fedora's doing GRUB updates don't overwrite /boot/efi/EFI/fedora with old bootloader binaries (not really the end of the world if it did happen I guess). > Or should I disable the boot loader spec in order to boot to Fedora 28 > on this machine ? I'm not sure that really helps get you closer to what you want. Anyway it's best if you tell us what your plan is for Fedora 28 going EOL this week. Are you making Fedora 30 primary in the near future? Or are you going to upgrade the Fedora 28 installation to Fedora 29? That sorta matters strategy wise. Maybe. -- Chris Murphy _______________________________________________ users mailing list -- users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to users-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://getfedora.org/code-of-conduct.html List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/users@xxxxxxxxxxxxxxxxxxxxxxx
