This guide is tailored to your current layout:
- Internal disk:
/dev/sda(489G) - Ubuntu EFI partition:
/dev/sda1(vfat, mounted at/boot/efi) - Ubuntu root partition:
/dev/sda2(ext4, mounted at/) - Backup USB (do NOT overwrite):
/dev/sdb(DataTraveler 2.0, mounted at/media/sam/EXTERNAL) - Installer USB target (for ISOs):
/dev/sdc(USB/Asolid) - Current boot mode: UEFI