Loss Of Dual-Boot After Upgrade [Solved]

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Loss Of Dual-Boot After Upgrade [Solved]

Postby VolvoBirkenstock » Wed Nov 08, 2017 3:53

Hello, Sabayon gurus.

I performed the weekly upgrade (sabayon weekly) yesterday evening. My system was dual-bootable with Sabayon Linux and Windows prior to this upgrade. Reboot subsequent to the upgrade shows the usual boot selection menu, but Windows is no longer listed as an option. "sudo fdisk -l" still illustrates the Windows and Linux partitions.

Can you tell me how to repair this dual-boot capability, or provide a link that describes how to effect a repair?

EDITED TO ADD: I have just looked at /boot/grub/grub.cfg. Apparently this recent upgrade has overwritten my grub.cfg file, and I suspect followed this action with something like "grub2-mkconfig -o /boot/grub/grub.cfg". I say this because the time associated with grub.cfg is the same as the upgrade time. So, how do I recreate grub.cfg so that it contains the information needed for dual-boot to both Sabayon Linux and Windows?

Thank you in advance very much,
Volvo
Last edited by VolvoBirkenstock on Thu Nov 09, 2017 3:30, edited 1 time in total.
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Re: Loss Of Dual-Boot After Upgrade

Postby sabayonino » Wed Nov 08, 2017 12:08

Hi

/boot/grub/grub.cfg is overwritten by grub2-mkconfig on every kernel update/upgrade. You shouln't edit this file

Seems there is a bug on os-prober.

Try to mount Windows partition(s) and run grub2-mkconfig . It will recognized Windows and/or other OSs and put them in the grub list
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Re: Loss Of Dual-Boot After Upgrade

Postby joost » Wed Nov 08, 2017 12:30

I noticed this happening too on baremetal dualboot setup machines.

I worked around this by creating a custom file for grub that gets included when you run grub2-mkconfig -o /boot/grub/grub.cfg (Or whenever Entropy installs OR removes a kernel)

So first edit /etc/grub.d/40_custom
Code: Select all
menuentry "Windows 10" { 
     insmod ntfs 
     set root='(hd0,1)' 
     search --no-floppy --fs-uuid --set a3f1ea41fc67a3f1 
     chainloader +1 
}


(to get the uuid use blkid /dev/sda1)

now regenerate grub.cfg:

Code: Select all
grub2-mkconfig -o /boot/grub/grub.cfg
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Re: Loss Of Dual-Boot After Upgrade

Postby joost » Wed Nov 08, 2017 13:35

I noticed that when I downgraded os-prober to version 1.74 everything worked normal again.
So expect this downgrade in Entropy ASAP. You can ignore what I wrote above. Once you have sys-boot/os-prober-1.74 installed on your system simply run:

Code: Select all
grub2-mkconfig -o /boot/grub/grub.cfg
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Re: Loss Of Dual-Boot After Upgrade

Postby sabayonino » Wed Nov 08, 2017 14:03

[Che Cos'è Il Calcolo Distribuito (BOINC)

BOINC ready ! Sabayon+BOINC = BILD ,my Sabayon spin :cyclops: - Ready to crunch for the Science everywhere :)
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Re: Loss Of Dual-Boot After Upgrade

Postby VolvoBirkenstock » Thu Nov 09, 2017 3:30

Thank you very much Joost and Sabayonino.
Very rapid root cause determination and solution delivery. :-)
The update/upgrade processes followed by "grub2-mkconfig -o /boot/grub/grub.cfg" fixed the problem.
Modifying Subject line to show Solved.
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