After a BIOS update, my Linux Mint installation stopped booting. I have two SSDs: one contains Linux Mint, while the other contains Windows 11 and appears to hold the EFI System Partition (ESP) used by Linux. I'm still learning how UEFI, the ESP, GRUB, and tools such as efibootmgr, chroot, mkdir, shimx64.efi, grubx64.efi, and bcdedit fit together. Before I run a repair command, I'd like to confirm the actual disk and partition layout and understand which repair method applies, so I don't accidentally modify the wrong drive.
2 Answers
Mint normally reuses an existing EFI System Partition during installation instead of creating another one. So if the Windows SSD has the only ESP and the Linux SSD has none, that is probably the layout Mint is using; there’s nothing inherently wrong with it. Confirm this from a Mint live session by checking the partitions and identifying the ESP mounted or labeled as an EFI partition. Once you know the correct disk, you can boot the installed system through a boot-repair utility or a bootloader recovery environment and reinstall GRUB from within Mint. If necessary, a live session can mount the installed system and use chroot to run the normal Mint GRUB installation commands. The important part is verifying the ESP and target disk first rather than blindly copying commands from a guide.
A simpler alternative is to use a boot-repair environment from a USB drive. Boot it in UEFI mode, select the recommended repair, and make sure you understand which SSD contains the EFI partition before applying anything. You can also use the firmware’s one-time boot menu to choose the Linux or Windows SSD directly. With two separate boot managers, selecting the drive from the firmware menu can keep the operating systems independent, although it is less convenient than having one GRUB menu manage both systems.
The issue had already been fixed by the time I saw this, but the explanation of using the firmware boot menu is useful for future troubleshooting.
Thanks—this explanation helped me understand why the EFI partition was on the Windows drive. I followed this approach and was able to repair the boot problem.