Can someone help me sort out a GRUB/GRUB2 issue with my laptop?

I did a fresh install to the internal HDD and wrote the boot to its
/dev/sda. The system only boots if I have both HDD drives installed.
If I remove the bay drive, boot fails with various errors.

Since /dev/sda is self contained complete install, I believe that I should be able to enable all three drives to boot.

• all drive show a grub menu to boot all drives
• SDD the primary source of boot for the speed advantages. Might also contain "root" folders and files used during boot as recovery option
• /dev/sda also bootable and holding all of the end-user and assorted folders and files.
• BAY also bootable

I have an internal HDD and an internal SSD. In addition, I have a dockiing station (port replicator) that has an HDD in a removable drive bay. This drive is not hot-swap.

I'm running Mint v21.3 with Cinnammon on the internal drive.
I have Mint 21.2 on the drive bay.
The box is supposed to boot from the SSD, but does not.

You omitted considerable relevant information, such as whether laptop has a UEFI BIOS, and if yes, whether CSM is enabled. Missing are whether you installed all OSes in legacy or UEFI mode, partitioning, whether SSD is an NVME device, which disks are GPT and which are legacy/MBR parititioned. Sharing lsblk -f and fdisk -l or parted -l plus all the fstabs will probably be necessary before all this is worked out to your satisfaction.

I'd start by disconnecting the dock and the removable drive, then rescue booting to chroot into an OS on sda to make booting work as expected from sda. If you now have the only SSD in a removable bay or the dock, yet want it to have primary boot control, move it to the internal non-removable spot before starting. From OP it's not clear to me where the SSD is installed and whether or not it is sata or possibly an nvme.

This should give you some novel ideas about how to setup boot menuing with all drives enabled.

My system is a Thinkpad with an Ultrabase "dock". The dock has a bay for either 2.5in drives or
a DVD writer.

• /dev/sda is the internal HDD with Mint 21.3
• /dev/sdb is the dock bay HDD with Mint 21.2
• /dev/nvmeXXX is the SSD desire to fast-boot into either Mint

I don't understand encough about how the grub/grub2 suite works to know how to write the boot details where I want them and then have grub/grub2 find the various details and create a menu. I certainly don't know how to create a grub/grub2 menu from scratch.

Thanks for your reply,
~~~ 0;-Dan

You forgot to post the output of the commands suggested in post 2. Additionally, the output of sudo efibootmgr -v from a terminal in Mint would be helpful if you are using an EFI system as Mint creates a directory on the EFI partition named 'ubuntu' and the 2nd install will overwrite the first install of the EFI boot files. This unless the first drive was not attached or was disabled during the install of the 2nd Mint.

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