Hello, I did a quick search and I believe this is the same or similar issue that I'm having after cloning my NVME 512 GB drive to a new 1 TB NVME.

I used Macrium Reflect to clone it and it seemed to work fine. I included a screen shot of my Disk Manager. The 161 GB partition is where my Ubuntu 24.04 resides. I cloned the NVME within Windows 11. I assumed that it would work based on some quick searches for Macrium Reflect dual boot. The Macrium Reflect software also saw this partition and cloned it. However, after I installed the replacement NVME it booted right to Windows. I confirmed that the BIOS boot order showed Ubuntu as the first OS. So, I used my USB thumb drive to boot to boot-repair tool. I ran the boot repair and it said it repaired the Dual boot but also came up with this message below.
https://imgur.com/w5LdMKY

https://imgur.com/C5a2e8q
Screen shot of Macrium Reflect showing all partitions including the 161 GB partition where Ubuntu is installed.
https://imgur.com/qk550gV
Screenshot of disk manager after clone was completed. Looks identical to Original NVME.
https://imgur.com/U4bdI4N


Based on my search results I believe I should attempt to boot off a Ubuntu Live CD and do what is mentioned in the linked post above?
Either do this:
1. Type sudo grub. Should get text of which last line is grub>
2. Type "find /boot/grub/stage1". You'll get a response like "(hd0,4)".
Use whatever your computer spits out for the following lines.
3. Type "root (hd0,4)",
4. Type "setup (hd0)", to install GRUB to MBR
5. Quit grub by typing "quit".
6. Reboot and remove the bootable CD.

Or boot off Live CD and restore GRUB via.

sudo grub-install /dev/sda

Thanks for any ideas!