How to restore GRUB menu in multiboot environment?

Naren(IND) · 05-12-2022, 09:12 PM

Hi...

I have upgraded my notebook with SSD harddrive. I am using my old HDD along with new SSD. Old HDD contians Windows 7, Windows 10 and RHEL 7.6 and installed in the notebook using HDD Caddy. New SSD installed in main slot contain windows 11. I have lost GRUB boot entry after installing Windows 11 os in SSD.
How can i restore GRUB along with all OS entries in the boot menu?

Thanks and Regards

Rickkkk · 05-13-2022, 08:28 AM

Hi Naren(IND),

Welcome to LinuxQuestions.

I am guessing that your laptop now boots from the new SSD drive and goes straight into Windows 11. If this is not the case, please specify.

If this *is* the case, it is expected. Once you install any version of Windows on a system where there are various other partitions and operating systems, the newly installed version of Windows sets itself up as if it were the only operating system on the computer.

In your case, your GRUB installation probably emanates from your RHEL installation. My method for restoring would be to boot a live ISO of RHEL, chroot into your existing RHEL installation, make sure your new SSD drive is visible to RHEL, reinstall GRUB and update your GRUB configuration (I'm not familiar with RHEL - this could be a command like "update-grub", "grub-mkconfig" or something else). Be careful to verify the various GRUB config files after doing this and make any fine-tuning adjustments before rebooting.

Hope this helps - please let us know if you require further assistance.

Cheers,

Rick

colorpurple21859 · 05-13-2022, 01:09 PM

Are you able to boot any of the other installations from the bios boot menu? The bios boot menu is usually accessed by one of the f-keys when the system is first started.

I suspect you may have mixed legacy/csm booting with uefi booting.
Did you make any changes in the bios/firmware to get windows11 to boot?

More details of your system setup can be given by the boot-info given by the boot-repair iso: https://sourceforge.net/projects/boot-repair-cd/files/

mrmazda · 05-13-2022, 08:32 PM

I agree with colorpurple21859.

Booting Linux by default again might be as simple as a change in BIOS setup, if your HDD was configured to boot using UEFI. If it was, simply reorder the boot devices priorities to return Linux to #1. Does RedHat or Grub show up in a list when you use your BBS menu hotkey?