I added more hard drives to my windows PC to dual boot as a test, then added another drive to actually play since I was enjoying Linux. My third OS isn’t bootable any more. What have I done wrong?

Started off with Windows 10 on a SATA drive with an M.2 drive for more data.

Added a 2Gb NVME with Debian - this has become my daily driver. I haven’t been to windows more than a few minutes a week.

Added another 250Gb SATA drive to test and play with another Debian install so I don’t break my daily driver.

Tried today to boot into the test OS and It’s just missing from GRUB? It doesn’t show up as a bootable drive in my UEFI BIOS either, though the drive itself is seen.

From KDE Partition Manager in my daily driver Debian, the drives are:

/dev/nvme01 - the daily driver Debian

/dev/sda - the Windows OS drive

/dev/sdb - the windows M.2 drive

/dev/sdc - the test Debian drive (not booting)

I would appreciate help. While there’s not much on that drive, I would like to continue my playing around.

Thanks in advance.

    • DeltaWingDragon@sh.itjust.works
      2·
      8 days ago

      If the Debians you installed weren’t Live ISOs, then I recommend Arch or Artix for CLI, and Manjaro or Ubuntu for GUI.

      You’ll have to mount the drives, chroot into the one on the drive that has the EFI partition, then grub-install and grub-mkconfig into the EFI partition.