Before this problem occurred, I deleted some unused kernels in the boot due to insufficient boot space (specifically -67, -109, -107, I am sure I am using 105, so it seems that those related to 105 have not been deleted), and downloaded the nvidia graphics driver on the ubuntu system. After the above operations were completed, I restarted the computer and the above problem occurredIn the grub selection page for entering the dual system, the ubuntu option disappeared, which made it impossible for me to enter the ubuntu system, as shown in the figure below.enter image description here
After encountering this problem, I tried to use rufus to create a boot disk, and then used the system on the USB disk to check the grub.cfg file in the original system. As a result, the file showed that there was no corresponding ubuntu option in the grub selection interface, only windows and other options.When I use the system on the USB drive to view the Ubuntu system files, I can't connect to the Internet, so I can't download some tools to help me fix the grub problem or give me some reference materials. I thought of a theoretically feasible but rather cumbersome, complicated and non-standard method: Can I directly modify the grub.cfg file and manually add an ubuntu item? But the problem with this is that I don't know how to write the specific parameters. Now I want to ask how to protect the data in the original ubuntu system as much as possible without destroying it, so that I can enter the ubuntu system normally?
