I'm trying to move my operating system from a 1TB M.2 drive to a smaller 500GB SSD to free up space. I cloned both the boot partition and the OS partition separately, and it seemed to go fine. However, when I start my laptop, I get to GRUB but it only boots from the original M.2 drive. If I remove the M.2 drive, GRUB still starts, but it times out while trying to boot from the SSD, dropping me into an emergency shell. I really don't know where I went wrong with the cloning or how to proceed. Any advice would be great, thanks!
4 Answers
It sounds like the problem might be with the GPT partition table. When you clone from a larger to a smaller drive, sometimes the end indexes aren't copied correctly. A utility like gdisk could potentially help you fix that.
How exactly did you go about cloning the drive? Sometimes the method can really affect how it boots after the clone.
I used Clonezilla for cloning the partitions.
A few things to check: What do you mean by 'OS partition'? Is it GPT or MBR, and are you booting in legacy mode or EFI? If using EFI, did your cloning include the EFI filesystem? Also, ensure you're not duplicating UUIDs after cloning; having the same UUIDs can cause boot issues. You might need to adjust GRUB settings afterwards too.
You could try editing some files on the SSD once you get access to it. Check the paths /efi/ubuntu/grub.cfg and /etc/fstab. Make sure the UUIDs inside those files match the new OS partition. After modifying that, you might be able to boot from the SSD. If you want, I have a script that manages this process for my setup, but it’s pretty specific to my installation. You can find it [here](https://pastebin.com/hbMQLARH) if you're curious, but proceed with caution if you decide to use it!
I actually reduced the OS partition down to 50GB and the boot partition is about 500MB. Both clones showed as successful when I checked, but I'll definitely give gdisk a try.