解决Ubuntu安装过程中的BIOS相关错误及启动项未显示问题

Hey there, sorry to hear you're stuck with this boot issue after installing Ubuntu—let's work through this step by step to get it sorted out! It sounds like the GRUB bootloader (which handles Ubuntu's startup) either wasn't installed correctly, or your BIOS/Windows is prioritizing the old Windows bootloader instead.

1. 先检查BIOS/UEFI的启动设置 #

First, let's make sure your BIOS isn't hiding Ubuntu or prioritizing Windows. Here's what to do:

• Restart your laptop and press the BIOS key as it boots up (this varies by brand: F2 for Dell/Lenovo, Del for ASUS, F12 for HP—keep an eye on the on-screen prompts)
• Once in BIOS, check these key settings:
  • Boot Mode: Ensure it matches what you used when installing Ubuntu. If you installed Ubuntu in UEFI mode, your BIOS should be set to UEFI (not Legacy/CSM). If you used Legacy, switch to that mode. Mismatched modes are a super common cause of missing boot entries.
  • Boot Order: Move your mechanical hard drive (where Ubuntu is installed) to the top of the boot priority list. If your old SSD is still connected, make sure it's not set as the first boot device—you could even disconnect the SSD temporarily to test, since the BIOS might fall back to it despite being faulty.
  • Secure Boot: Try disabling this if it's enabled. Some UEFI systems block unsigned bootloaders like GRUB, which can prevent Ubuntu from showing up in boot options.

2. 用Ubuntu安装介质修复GRUB引导 #

If adjusting BIOS settings doesn't work, the next step is to repair the GRUB bootloader directly. You'll need your original Ubuntu installation USB/disk:

• Plug in the installation media and restart your laptop, booting from the USB (use the boot menu key, usually F12, to select it)
• Choose "Try Ubuntu without installing" to load the live environment
• Open the terminal (find it in the apps menu, or press Ctrl+Alt+T)
• First, identify which partition has your Ubuntu installation. Run this command to list all drives/partitions:

  sudo fdisk -l
  

  Look for a partition labeled Linux filesystem—this is your Ubuntu root partition (it might be something like /dev/sda1 or /dev/sdb1, depending on your setup)
• Mount that partition to the live environment:

  sudo mount /dev/sda1 /mnt
  

  Replace /dev/sda1 with your actual Ubuntu partition path
• If you're using UEFI mode (most modern laptops), you'll also need to mount the EFI system partition (ESP). Find it with sudo fdisk -l (it's usually a small partition labeled EFI System), then mount it:

  sudo mount /dev/sda2 /mnt/boot/efi
  

  Again, replace /dev/sda2 with your ESP path
• Now reinstall GRUB to your mechanical hard drive:

  sudo grub-install --boot-directory=/mnt/boot /dev/sda
  

  Replace /dev/sda with the disk name (not partition) of your mechanical hard drive (e.g., /dev/sdb if it's the second drive)
• Update GRUB to detect all installed operating systems:

  sudo update-grub
  

• Reboot your laptop, remove the installation media, and check if the GRUB menu appears now.

3. 修复Windows引导管理器的干扰 #

If you still see the Windows boot menu, it might be that Windows overwrote the bootloader. You can fix this from Windows:

• Boot into Windows (since it's still loading)
• Open Command Prompt as an administrator (right-click Start > Command Prompt (Admin))
• Run this command to set GRUB as the default bootloader:

  bcdedit /set {bootmgr} path \EFI\ubuntu\grubx64.efi
  

• Restart your laptop—you should now see the Ubuntu GRUB menu.

额外提示 #

• If your faulty SSD is still connected, consider disconnecting it temporarily while troubleshooting. Sometimes the BIOS tries to boot from the SSD even if it's broken, which can mess with boot priorities.
• If you're not sure whether you installed Ubuntu in UEFI or Legacy mode, check the live environment: run ls /sys/firmware/efi—if the directory exists, you used UEFI; if not, it's Legacy.

备注：内容来源于stack exchange，提问作者SHANKS