戴尔Inspiron笔记本Grub菜单消失，双系统无法引导求助

Hey there, let’s work through this boot problem together—it’s a common hiccup with dual-boot Dell Inspirons, so we’ve got a clear plan to get your systems back up. Here’s what to do step by step:

First, you’ll need a working computer to make a rescue USB. Grab a 4GB+ USB drive, then:

• Download the same Ubuntu version you had installed from the official Ubuntu site
• Use a tool like Rufus or Etcher to write the ISO file to the USB drive (make sure to select the correct USB device to avoid overwriting other data)

Plug the USB into your Inspiron, then restart it. As soon as you see the Dell logo, press F12 to open the boot menu. Select your USB drive from the list, then choose "Try Ubuntu without installing" when prompted—this lets you access a live Ubuntu environment without touching your installed system.

Before fixing GRUB, we need to make sure your Ubuntu partitions aren’t corrupted or missing:

• Open the Disks app (search for it in the live environment’s menu)
• Look for your main Ubuntu partition (it’ll be formatted as ext4) and the EFI system partition (small, ~100-500MB, formatted as FAT32) if you’re using UEFI boot
• If you can’t find these partitions, you might be dealing with disk corruption or accidental deletion—skip to Step 6. If they’re there, move on to repairing GRUB.

GRUB is probably corrupted or got overwritten. The fix depends on whether your system uses UEFI or BIOS/MBR boot. To check:
Open a terminal (Ctrl+Alt+T) and run:

ls /sys/firmware/efi

If the command returns a list of files/folders, you’re on UEFI. If it says "No such file or directory", you’re on BIOS/MBR.

For UEFI Systems #

1. Find your EFI partition’s device name (e.g., /dev/nvme0n1p1 or /dev/sda1) using the Disks app
2. Mount the EFI partition and your Ubuntu root partition:

   sudo mount /dev/your-efi-partition /mnt/boot/efi
   sudo mount /dev/your-ubuntu-root-partition /mnt
   

3. Bind critical system directories to the mounted partition:

   sudo mount --bind /dev /mnt/dev
   sudo mount --bind /proc /mnt/proc
   sudo mount --bind /sys /mnt/sys
   

4. Switch to your installed Ubuntu’s root environment:

   sudo chroot /mnt
   

5. Reinstall GRUB to your disk (note: use the disk name, not a partition—e.g., /dev/nvme0n1 or /dev/sda):

   sudo grub-install /dev/your-disk-name
   

6. Update the GRUB configuration to detect both Ubuntu and Windows:

   sudo update-grub
   

7. Exit the chroot environment and reboot:

   exit
   sudo reboot
   

Don’t forget to unplug the USB after rebooting.

For BIOS/MBR Systems #

1. Mount your Ubuntu root partition:

   sudo mount /dev/your-ubuntu-root-partition /mnt
   

2. Reinstall GRUB to your disk:

   sudo grub-install --root-directory=/mnt /dev/your-disk-name
   

3. Update GRUB to detect both systems:

   sudo update-grub
   

4. Reboot your computer, removing the USB drive.

If GRUB still doesn’t show up, boot into BIOS by pressing F2 when your Dell starts up, then verify these settings:

• Secure Boot: Set this to Disabled—Secure Boot can block GRUB from loading, and restoring BIOS defaults might have re-enabled it
• Boot Order: Make sure the entry for Ubuntu (or your main hard drive) is at the top of the boot list
• SATA Operation: Ensure this is set to AHCI—some Dell laptops default to RAID, which can cause boot issues with dual-boot setups (even if it worked before, restoring defaults might have changed this)

If none of the above works, your hard drive/SSD might be failing. In the live Ubuntu environment:

• Open the Disks app, select your main disk, then click the three-dot menu > SMART Data & Self-Tests
• Run the Short Self-Test—if it returns any errors, your disk is likely faulty and needs replacement.

内容的提问来源于stack exchange，提问作者Dinil Sennath