Two ways to fix UEFI boot for Windows and Ubuntu dual system

Check to see if Ubuntu is booting from Efi/uefi: If/sys/firmware/efi exists then yes, otherwise not. Shell command:

[-d/sys/firmware/efi] && echo UEFI | | Echo BIOS

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After reading my installation of the Ubuntu and Windows 8 dual-system tutorials, the main problem is that the computer is booting directly to Windows 8 without the option to start Ubuntu.

Here are two ways to fix the EFI boot boot so that Ubuntu can start normally

Set GRUB2 to boot boot

1. Enable GRUB Boot

There may be problems in some places during installation.

Theoretically, if you first install Ubuntu, then you need to turn off quick start.

I hope you follow this guide to create a uefi Ubuntu boot USB flash drive to install the correct UEFI boot program.

If you have done these things at the time of installation, the possible error is to set GRUB2 as the boot manager.

You can set GRUB2 as the default bootstrapper by following several steps:

1. Log in to Windows 8
2. Go to the desktop
3. Right-click the Start button and select Admin command line
4. Input Mountvol g:/s (this maps your EFI directory structure to G-disk)
5. Input CD G:\EFI
6. When you enter Dir to List Folder contents, you can see an Ubuntu folder
7. The parameters here can be Grubx64.efi or shimx64.efi.
8. Run the following command to set Grub64.efi as the boot loader: bcdedit/set {bootmgr} path \efi\ubuntu\grubx64.efi
9. Restart your computer
10. You'll see a grub menu with Ubuntu and Windows options
11. If your computer is still booting directly to Windows, repeat steps 1 through 7, but this time input: bcdedit/set {bootmgr} path \efi\ubuntu\shimx64.efi
12. Restart your computer

All you have to do here is log on to the Windows Administrator command line, map the EFI boot area to disk to see if the Ubuntu Bootstrapper is successfully installed, and then choose Grubx64.efi or Shimx64.efi as the bootloader.

So what's the difference between Grubx64.efi and Shimx64.efi? In the case of Secure Boot (serureboot) shutdown, you can use Grubx64.efi. If secure boot is on, you need to select Shimx64.efi.

In my steps above, I suggest trying one first, and then try another one. Another option is to select one and then enable or disable secure boot in the BIOS based on the boot program you choose.

2. Use Refind to boot Ubuntu and Windows dual system

The Refind boot program lists all of your operating systems as icons. Therefore, you can start the operating system in Windows, Ubuntu, or a USB flash drive by clicking on the appropriate icon.

Click here to download refind for Windows 8.

After downloading and decompression, follow the steps below to install the refind.

1. Back to Desktop
2. Right-click the Start button and select Admin command line
3. Input Mountvol g:/s (this maps your EFI directory structure to G-disk)
4. Enter the extracted Refind directory. For example: CD c:\users\gary\downloads\refind-bin-0.8.4\refind-bin-0.8.4. When you enter the dir command, you can see a refind directory
5. Enter the following command to copy the Refind to the EFI boot area xcopy/e refind g:\EFI\refind\
6. Enter the following command to enter the Refind folder CD G:\EFI\refind
7. Renaming the sample configuration file Rename Refind.conf-sample refind.conf
8. Run the following command to set Refind to bootstrapper bcdedit/set {bootmgr} path \efi\refind\refind_x64.efi
9. Restart your computer
10. You'll see a graphical menu with Ubuntu and Windows

This process is very similar to choosing the Grub boot program.

Simply put, the main is to download Refind, unzip the file. Copy the file to the EFI boot area, rename the configuration file, and then set the Refind as the boot program.

Two ways to fix UEFI boot for Windows and Ubuntu dual system