How to fix Linux boot failure issue.

If Linux fails to boot up, you can try the following troubleshooting methods:

1. Check boot settings: Verify that the boot settings in the system are correct. You can try reinstalling the boot loader (such as GRUB) or repairing the boot settings.
2. Check hardware issues: Verify if hardware connections are correct, such as ensuring the hard drive is properly connected and there is sufficient power supply.
3. Restore the boot partition: You can enter recovery mode using a Linux installation CD or USB boot drive to reinstall or repair the boot partition.
4. Utilizing a backup system: If a backup system (such as dual boot) is available, you can attempt to boot into the backup system and repair or restore the Linux system from there.
5. Utilize a boot repair tool: You can use various boot repair tools like Boot-Repair to fix boot problems.
6. Utilize a Live CD or USB: You can use a Live CD or USB boot disk for Linux to enter the system’s rescue or recovery mode and perform repair operations.

If the above methods fail to solve the problem, you may need to seek further help from the Linux community or technical support.