MBR2GPT.exe is a command line tool which is located in the System32 folder in Windows 10. Generally this setting is located in the Boot tab → Boot order section of the BIOS. Set up your BIOS so that it boots the HDD in Legacy mode.Click the Apply button in the lower right corner.Uncheck the Separate /boot/efi partition option.If Ubuntu is installed on a GPT disk (you can check it via the sudo parted -l command), use GParted partition editor to create a BIOS-Boot partition (1MB, unformatted filesystem, bios_grub flag) at the start of its disk.(Graphics cards are a common source of problems.) Converting to boot in BIOS/CSM/legacy mode while Windows boots in UEFI mode can make the boot process more awkward - you'll need to use the computer's built-in boot manager to switch between OSs, and some computer's have such poor boot managers that this may be impossible. Such a conversion may be necessary if some hardware doesn't work correctly under UEFI mode. Note: Use this procedure only to convert an UEFI mode Ubuntu installation to boot in BIOS/CSM/legacy mode. The way to adjust this setting depends on the specific model of the computer, but generally this setting is located in the boot priority settings under the Boot tab of the BIOS/UEFI setup utility. Set up your BIOS so that it boots the hard drive in UEFI mode.If you see a Separate /boot/efi partition option, put a checkmark in the checkbox to the left of it, then click the Apply button in the lower right corner.
If you have installed Ubuntu in legacy mode on the same drive with GPT partitioning, you can use Boot Repair's Advanced options to uninstall grub-pc and install grub-efi-amd64. In the new window that opens up look for the entry after where it says BIOS Mode. To check if your Windows is installed in UEFI, press the keyboard combination Windows + r then enter the command msinfo32 in the Run window. If your Windows is installed in BIOS mode, it is recommended to install your Ubuntu in BIOS mode, but if it's installed in UEFI mode, then do the same with Ubuntu. If the OSs were installed in different modes, dual booting Windows and Ubuntu with grub can't work. Then reboot the computer with sudo reboot Open the Boot Repair application and select Advanced Options -> Main Options tab -> check Reinstall GRUB and Unhide boot menu as shown in the below screenshot. From an Ubuntu live session open the terminal and type: sudo add-apt-repository ppa:yannubuntu/boot-repair Ubuntu live session from the USB flash drive that you used to install Ubuntu, and repairing the GRUB bootloader with Boot Repair. Select Ubuntu from the GRUB menu and press Enter.įrom Ubuntu open the terminal and type: sudo update-grub & sudo reboot With UEFI press (perhaps several times) the Esc key to get to the GNU GRUB menu screen. Immediately after the motherboard / computer vendor logo splash screen appears when the computer is booting, with BIOS, quickly press and hold the Shift key, which will bring up a GNU GRUB menu screen. To identify the partition numbers use GParted - it is included in the Ubuntu installation media.īoot into BIOS and select Ubuntu in UEFI settings to be the default operating system to boot. SdX = disk | sdXX = efi partition | sdXXX = system partition Re-install the GRUB boot loader to your Ubuntu installation in EFI mode.īoot from the Ubuntu installation media - open a terminal and execute: sudo mount /dev/sdXXX /mntįor i in /dev /dev/pts /proc /sys /run do sudo mount -B $i /mnt$i done In case there is no Ubuntu entry to be found in the BIOS / UEFI settings, Select Energy Settings, enable show hidden settings and uncheck Fast Boot.Īfter having done this - shutdown the computer completely - do NOT reboot.īoot into the BIOS and select Ubuntu as the default operating system to boot. Open the legacy version of the Windows Control Panel (not the modern version). Open command prompt as administrator and execute : powercfg /h off Disable the hibernation mode and Fast Boot in Windows.