Grub Gone While Re-installing Leap 15.6

[oldcpu]

@PrakashC

When I tried installing 15.6 again the Open SUSE did not show up at the disk utilisation stage. The SSD does show up in the F12 booting menu but not in the installation process. So I tried to boot into the SSD from F12 menu and ran into Grub Rescue. It appears that unless grub is repaired I cannot proceed further.

I have tried to repair grub by booting from portable SSD, mounting the 15.5 partition as its grub files will be intact, chroot to 15.5 partition and issued grub-install /dev/sdb (that is the target SSD). However I got error message ‘command not found’. What am I doing wrong? And what should I do?

Let me tell you my experience, and you can decide how much, if any of this, is applicable to you.

Early on, when I was setting up and tuning my external SSD enclosure (which has a 1 TB SSD inside) I managed to somehow mess up the LEAP-15.6 grub boot configuration on my laptop’s SSD. I posted about this a thread about my external SSD enclosure.

Planning to make an external nvme SSD my backup PC

Thankyou for the suggestion. I adopted a bit of a different approach. Since I was running the LEAP-15.6 that was previously (and still) on my Lenovo laptop (with only Grub screwed up) instead I (successfully I think) did the following: oldcpu@lenovo:~> sudo su - lenovo:~ # grub2-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=openSUSE_Internal --recheck Installing for x86_64-efi platform. Installation finished. No error reported. and then I ran grub.cfg lenovo:~ # grub…

The external SSD thou (also with LEAP-15.6) was in good shape and I could boot to it.

So with my laptop’s power off, I connected the external SSD enclosure to my laptop, and I booted to the external SSD’s LEAP-15.6.

Running LEAP from the external SSD, I could see in YaST that the external SSD’s partitions were labelled nvme0n1px (where x was 1 to 7). I could see in YaST that the internal SSD partitions ere all labelled sdax (where x was 1 to 4).

My recollection is I opened a bash shell, and did the following:

oldcpu@lenovo:~> sudo su -
lenovo:~ # grub2-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=openSUSE_Internal --recheck
Installing for x86_64-efi platform.
Installation finished. No error reported.

As opposed to starting with sudo su - you could just put sudo in front of each command.
I then followed it up with grub2-mkconfig (see below)

lenovo:~ # grub2-mkconfig -o /boot/grub2/grub.cfg
Generating grub configuration file ...
Found theme: /boot/grub2/themes/openSUSE/theme.txt
Found linux image: /boot/vmlinuz-6.4.0-150600.23.53-default
Found initrd image: /boot/initrd-6.4.0-150600.23.53-default
Found linux image: /boot/vmlinuz-6.4.0-150600.23.47-default
Found initrd image: /boot/initrd-6.4.0-150600.23.47-default
Warning: os-prober will be executed to detect other bootable partitions.
Its output will be used to detect bootable binaries on them and create new boot entries.
5010.132769 | DM multipath kernel driver not loaded
Found Windows Boot Manager on /dev/nvme0n1p1@/EFI/Microsoft/Boot/bootmgfw.efi
Found openSUSE Leap 15.6 on /dev/sda3
Adding boot menu entry for UEFI Firmware Settings ...
done
lenovo:~ #

So, you may well ask why did I do this? I do NOT know this stuff off of the top of my head, but I did know before such was and is doable. So this is a summary of what I read on the internet:

The openSUSE command ( grub2-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=openSUSE_Internal --recheck ) installs the GRUB2 bootloader for UEFI systems. Here is a break down each part:

• grub2-install - The main command that installs GRUB2 bootloader files
• --target=x86_64-efi - Specifies the target platform as 64-bit x86 UEFI (as opposed to legacy BIOS or other architectures)
• --efi-directory=/boot/efi - Points to the EFI System Partition mount point where UEFI bootloader files will be installed. This is typically a FAT32 partition mounted at /boot/efi … given your PC has two SSDs I do not know how much of this is applicable to you.
• --bootloader-id=openSUSE_Internal - Sets a custom identifier for this bootloader entry. This creates a directory called openSUSE_Internal in the EFI partition and registers it with the UEFI firmware. If successful, this should appear in the system’s boot menu
• --recheck - Forces GRUB to re-examine the device map and partition layout, ensuring it has current information about available drives and partitions

I read this command is typically used when:

• Installing openSUSE on a UEFI system
• Repairing a broken GRUB installation
• Setting up a custom bootloader configuration
• Moving from BIOS to UEFI boot mode

The “Internal” suffix in the bootloader ID suggests this might be for an internal testing or development setup rather than a standard end-user installation.

=== BUT that was not the only command I sent - also sent grub-mkconfig … Why?

The command ( grub2-mkconfig -o /boot/grub2/grub.cfg ) generates a new GRUB2 configuration file for openSUSE LEAP 15.6:

• grub2-mkconfig - The utility that automatically generates GRUB2 configuration by scanning a system
• -o /boot/grub2/grub.cfg - Specifies the output file location where the generated configuration will be written. This is GRUB2’s main configuration file that it reads during boot

I read that here is what happens when this command runs:

1st - System Scanning:

• it detects all installed operating systems (Linux kernels, Windows, etc.)
• it finds available kernel versions in /boot
• it checks for recovery/rescue kernels
• it looks for other bootable operating systems on different partitions

2nd - Configuration Generation:

• it creates boot menu entries for each found kernel
• it sets up proper kernel parameters and initrd paths
• it applies settings from /etc/default/grub (timeout, default boot option, etc.)
• it includes any custom entries from /etc/grub.d/ scripts

openSUSE LEAP 15.6 Specifics:

• it will typically find the main kernel and any installed kernel flavors
• it may include YaST2 bootloader settings
• it creates entries for normal boot and recovery modes

This command is commonly run after:

• Installing a new kernel
• Changing GRUB settings in /etc/default/grub
• Adding/removing operating systems
• The previous grub2-install command (to ensure the newly installed bootloader has current configuration)

The combination of these two commands essentially reinstalls GRUB2 and rebuilds its configuration from scratch.

I have not (yet) examined your computer’s partitioning structure in detail - so I can not say with confidence that this approach will work for you. If it were me, in this case, if I were you, I probably would check this a bit more.