I can't seem to boot out of the Xubuntu 20.04 in a duplicated partition to my initial / root partition.
My only operable OS on my machine was Xubuntu 20.04, mounted as / on a partition nvme0n1p3. I wanted to add another partition and install the root / mount point for Ubuntu 24.04 into it. I ran into issues whereby the manual partitioner couldn't recognize my /boot/efi partition (similar to this). My guess at the moment is that Ubuntu 24.04 can't proceed with the install because it requires that initial partition to be 1 GiB, not the 512 MiB that more than sufficed under Xubuntu 20.04.
SO, I'm trying to make space to enlarge that first partition, which means I need to effectually move the nvme0n1p3. The steps that made the most sense were to:
- create a new partition (nvme0n1p4) off the end of the current nvme0n1p3 partition, with a gap of 2 GiB
- Duplicate the old Xubuntu 20.04 from the original (nvme0n1p3) to the new partition (nvme0n1p4)
- Once convinced that I can boot and run out of the duplicated (nvme0n1p4) partition, delete the original partition ((nvme0n1p3)
- Resize the vfat /boot/efi partition to 2.5 GiB (more than necessary, but a precaution against similar issues in the future)
- Create a new nvme0n1p3 partition (it might not get called that) between the boot and nvme0n1p4 partitions, but just leave it empty for now
- Create a new partition (nvme0n1p5) partition in the unallocated space to the "right" of the existing partitions, and eventually install (hopefully) Ubuntu 24.04 into it.
I'm stuck between steps 2 and 3. The finer detail is:
- Use gparted to do the partitioning described above
- Re-boot off of the Ubuntu 24.04 USB stick (so that all partitions can be unmounted)
- dd the existing nvme0n1p3 partition to the new nvme0n1p4 partition
- Follow along here to give the new partition a unique UUID and edit the /etc/fstab entry in the nvme0n1p4 partition accordingly
- Run
update-grub, and confirm new menu entries in /boot/grub/grub.cfg - Attempt to boot into the cloned-Xubuntu 20.04 nvme0n1p4 partition
I am apparently able to select the right menu option in the grub menu, but it boots me into the original nvme0n1p3 partition.
Some details:
sudo lsblk -f:
nvme0n1
| - | - | - | - | - | - |
|---|---|---|---|---|---|
| ├─nvme0n1p1 | vfat | 995C-7BB0 | 469M | 1% | /boot/efi |
| ├─nvme0n1p2 | swap | e67db830-5b33-41bb-859d-8ab967d79db6 | [SWAP] | ||
| ├─nvme0n1p3 | ext4 | 63c24e20-9e18-4b6d-9091-5289f1398d61 | 21.8G | 65% | / |
| ├─nvme0n1p4 | ext4 | e3a93f78-5ba8-445a-9a9f-bcd95aabd7dd | |||
| └─nvme0n1p5 | ext4 | d777c31a-6fb1-4b27-bedd-1d5400569eee |
sudo fdisk -l
| Device | Start | End | Sectors | Size | Type |
|---|---|---|---|---|---|
| /dev/nvme0n1p1 | 2048 | 976895 | 974848 | 476M | EFI System |
| /dev/nvme0n1p3 | 976896 | 157227007 | 156250112 | 74.5G | Linux filesystem |
| /dev/nvme0n1p4 | 161323008 | 325163007 | 163840000 | 78.1G | Linux filesystem |
| /dev/nvme0n1p5 | 325163008 | 489003007 | 163840000 | 78.1G | Linux filesystem |
| /dev/nvme0n1p2 | 945522688 | 976771071 | 31248384 | 14.9G | Linux swap |
I understand that one shouldn't edit the /boot/grub/grub.cfg file directly, but I'm a little puzzled at entries like
menuentry 'Ubuntu 20.04.6 LTS (20.04) (on /dev/nvme0n1p4)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'osprober-gnulinux-simple-e3a93f78-5ba8-445a-9a9f-bcd95aabd7dd' {
insmod part_gpt
insmod ext2
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root e3a93f78-5ba8-445a-9a9f-bcd95aabd7dd
else
search --no-floppy --fs-uuid --set=root e3a93f78-5ba8-445a-9a9f-bcd95aabd7dd
fi
linux /boot/vmlinuz-5.15.0-127-generic root=UUID=63c24e20-9e18-4b6d-9091-5289f1398d61 ro quiet splash $vt_handoff
initrd /boot/initrd.img-5.15.0-127-generic
}
update-grub appears to pick up the new UUID through most of the entry, but ultimately retains the old UUID in the "linux /boot/vmlinuz-5.15.0-127-generic" line. If this is the problem, update-grub is evidently getting the wrong info from somewhere I haven't found yet. Is that the problem? What else am I missing?
update-grub itself doesn't suggest there should be any problems:
Sourcing file '/etc/default/grub'
Sourcing file '/etc/default/grub.d/init-select.cfg'
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-5.15.0-127-generic
Found initrd image: /boot/initrd.img-5.15.0-127-generic
Found linux image: /boot/vmlinuz-5.15.0-125-generic
Found initrd image: /boot/initrd.img-5.15.0-125-generic
Found Ubuntu 20.04.6 LTS (20.04) on /dev/nvme0n1p4
Adding boot menu entry for UEFI Firmware Settings
done
EDIT/ADDED: Curiously, the non-booting nvme0n1p4 partition is in the os-prober portion of grub.cfg. This suggests it should be in the 10_linux section. update-grub seems to be getting it wrong?
Edit #2: The answer in this question convinced me to go off piste and edit /boot/grub/grub.cfg by hand and try rebooting. I moved the nvme0n1p4 partition / root to the 10_linux section, and replaced the ...-5289f1398d61 lines to ...-bcd95aabd7dd. Selecting the same menu item as before this time booted me into this partition. So, success, except I wasn't supposed to edit that file by hand.
And, running (this time) sudo update-grub2, the original nvme0n1p3 / root winds up in the 30_os-prober section, the expected reciprocal of before, though this time all UUIDs in all the menu and submenu blocks show ...-5289f1398d61.
