Convertire un'installazione Debian da Legacy BIOS a UEFI

=Riferimenti= *Convert a disk from MBR to GPT+UEFI, in Linux. · GitHub

Attenzione questo articolo è ancora incompleto. Sentiti libero di contribuire cliccando sul tasto edit.

Before starting, make sure you have a backup, and make sure to have a linux live boot ready to rescue your system. It’s easy to mess this up!

1. Use gdisk to convert the partition table to GPT. > gdisk /dev/sda

2. Create the “BIOS boot” partition that GRUB needs. > n to create a new partition. Needs to be about 1MB. You can probably squeeze this in from sectors 34-2047. Use L or l to look up the code for “BIOS boot” (ef02).

3. Write the new partition table. > w

4. Reload the partition table. > partprobe /dev/sda

5. Re-install the GRUB boot loader using the new partition scheme. > grub-install /dev/sda

   Optionally reboot to verify it’s working. If you just need GPT and not UEFI, you can stop here.

   ---

6. Use gdisk to add an “EFI System” partition (ESP). Officially should be 100-500MB, but mine only used 130kB. Can be anywhere on the disk, so consider putting it at the end if you’re using non-resizable media like a physical disk. > gdisk /dev/sda and use n to create the partition.

7. Give the ESP a distinctive label without whitespace like EFI-system, because we’ll reference the partition label in fstab. > c to set the label.

8. Write the partition table. > w

9. Reload the partition table. > partprobe /dev/sda

10. Build the filesystem for the ESP. > mkfs -t vfat -v /dev/disk/by-partlabel/EFI-system

11. Create the ESP mount point. > mkdir /boot/efi

12. Add the ESP to /etc/fstab. It should look like this: > /dev/disk/by-partlabel/EFI-system /boot/efi vfat defaults 0 2

13. Mount the ESP. > mount /boot/efi

14. Install the GRUB EFI package. > apt install grub-efi

15. Install the GRUB EFI bootloader onto the disk. > grub-install --target=x86_64-efi /dev/sda

16. Reboot.

17. Change the BIOS from BIOS boot to UEFI boot.

18. Use the one-time boot menu to force boot the disk. You may have to navigate to the disk -> EFI -> ubuntu -> grubx64.efi.

19. Re-install GRUB’s EFI bootloader to update the UEFI boot selector. > grub-install

Resources

• The author of gdisk has a verbose description of MBR, GPT, and UEFI.
• https://serverfault.com/questions/765778/clonezilla-restore-mbr-disk-to-4tb-disk-convert-to-gpt-linux-not-windows covers the first part of the process.