[Resolved] Upgrade to Fedora 30 fails and yields a grub prompt

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grayfox
Posts: 76
Joined: 10. Aug 2008, 20:51

[Resolved] Upgrade to Fedora 30 fails and yields a grub prompt

Post by grayfox »

Hi,
I upgraded to VB0X 6.0.10 this afternoon and my Fedora 29 VM worked fine ( MacOs 10.14.6 host).

When I tried to upgrade the VM to Fedora 30 all goes well until the reboot.

The reboot yields a grub prompt.

Attempting to manually boot by specifying a linux kernel and an initramfs starts ok
but the kernel swap fails...

Doing ; grub> ls / shows kernel stuff it looks like boot directory on my 'real' fedora boot directory.

Has anyone else have this problem?

Thanks
Last edited by socratis on 13. Aug 2019, 22:31, edited 1 time in total.
Reason: Marked as [Resolved].
socratis
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Posts: 27330
Joined: 22. Oct 2010, 11:03
Primary OS: Mac OS X other
VBox Version: PUEL
Guest OSses: Win(*>98), Linux*, OSX>10.5
Location: Greece

Re: Upgrade to Fedora 30 fails and yields a grub prompt

Post by socratis »

Moving to "Linux Guests" from "OSX Hosts", this has nothing to do with your Host, and everything to do with your Guest.
Do NOT send me Personal Messages (PMs) for troubleshooting, they are simply deleted.
Do NOT reply with the "QUOTE" button, please use the "POST REPLY", at the bottom of the form.
If you obfuscate any information requested, I will obfuscate my response. These are virtual UUIDs, not real ones.
piggyz
Posts: 70
Joined: 13. Feb 2013, 12:28

Re: Upgrade to Fedora 30 fails and yields a grub prompt

Post by piggyz »

This problem have nothing to do with virtualization. You will get the same even on a real machine. Ir is a problem with the new Fedora 30 BLS boot techlogy. Look at the grubby command to solve the problem, and Google is your friend.
grayfox
Posts: 76
Joined: 10. Aug 2008, 20:51

Re: Upgrade to Fedora 30 fails and yields a grub prompt

Post by grayfox »

You are correct and someone in the Fedora newsgroup pointed me to the solution which works...
If you have a legacy BIOS installation (i.e. not UEFI), it is possible that after the upgrade process the GRUB bootloader will not populate the boot menu, and instead displays a GRUB prompt. This happens on systems that were originally installed using Fedora 20 or older.

This happens because the GRUB core and modules in legacy BIOS are never updated unless the grub2-install command is executed. In Fedora 30 the default GRUB configuration is changed to use BootLoaderSpec-style files by default, and the blscfg module is updated when the Package-x-generic-16.pnggrub2-pc-modules package is upgraded. However, this module is only compatible with versions of the GRUB core up to Fedora 21.

If GRUB has not been updated since Fedora 20 or earlier, it is recommended to execute the grub2-install command before doing a system upgrade. This should not affect legacy BIOS installations since Fedora 21. UEFI installs are unaffected because during upgrade the GRUB EFI image, containing the core and modules, is updated.

If you hit this issue, the old GRUB configuration is stored in /boot/grub2/grub.cfg.rpmsave. So the system can be recovered by executing the following from the GRUB prompt:

grub> configfile /grub2/grub.cfg.rpmsave
And then execute the grub2-install /dev/X command (where X is the boot device, i.e sda) to update the GRUB core and the modules to the latest version installed by the Package-x-generic-16.pnggrub2-pc-modules package.
socratis
Site Moderator
Posts: 27330
Joined: 22. Oct 2010, 11:03
Primary OS: Mac OS X other
VBox Version: PUEL
Guest OSses: Win(*>98), Linux*, OSX>10.5
Location: Greece

Re: Upgrade to Fedora 30 fails and yields a grub prompt

Post by socratis »

Thanks @piggyz for the pointer and @grayfox for quoting the solution. Marking as [Resolved].
Do NOT send me Personal Messages (PMs) for troubleshooting, they are simply deleted.
Do NOT reply with the "QUOTE" button, please use the "POST REPLY", at the bottom of the form.
If you obfuscate any information requested, I will obfuscate my response. These are virtual UUIDs, not real ones.
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