Ubuntu – Ubuntu 14.04.3 LTS with Windows 10 UEFI GUID custom installation

dual-bootgrub2ltsuefi

I have used Ubuntu for many years and someone gave me a computer with Windows 8, later updated to 8.1 and, finally, to 10.
The thing is I want to install Ubuntu LTS (14.04.3) alongside Windows 10 (dual boot), and because of my personal circumstances I need to use the "custom installation" feature. UEFI boot, guid/gpt partition table. The ubuntu live pendrive is booted in UEFI mode.
When I started the custom installation it asked me where to install grub. I selected the whole disk (dev/sda) and continued. When it finished and rebooted, it booted into Windows 10, and Windows 10 doesn't recognize any other OSes. It's because of the UEFI partition, with only Windows boot manager installed.
So what do I need to do in order to install grub in the UEFI partition without deleting Windows Boot Manager? Do I just have to select "Install GRUB in dev/sda2 (UEFI partition)"? Will it keep Windows Boot Manager, as said in the UEFI wiki article? (I have read many post and the uefi article but none of them say what to do in my case.)
Thanks
Quotes from the wiki:
"If your disk already contains an ESP (eg if your computer had Windows 8 preinstalled), it can be used for Ubuntu too. Do not format it."

"Note that in a UEFI-mode installation, Ubuntu will not ask you where to install the boot loader. If it does, or if it complains about the lack of a BIOS Boot Partition, you've probably accidentally booted in BIOS/CSM/legacy mode."

Best Answer

Ubuntu 14.04.3 LTS with Windows 10 UEFI GUID custom installation

Details of the system in which I have successfully installed Ubuntu 14.04 LTS:

  • DELL Inspiron 11 (2-IN-1, 3158)
  • Processor - Intel core i3 - 6100U
  • RAM - 4.00 GB
  • UEFI secure boot enabled
  • HDD - 500GB GUID
  • Pre-installed OS - Windows 10 Home Single Language

Steps to install Ubuntu 14.04 LTS alongside Windows 10 and without overwriting Windows Boot Manager:

Pre-requisites:

  • 50GB un-allocated HDD space
  • Bootable USB of Ubuntu 14.04 (64bit)
  • Disable "Turn on fast startup" in Windows 10

Installation Procedure

  • Boot system with Ubuntu 14.04 USB in 'UEFI secure boot enabled' mode.

  • Select Live session.

  • Double click 'Install Ubuntu' icon on desktop to begin installation.

  • Installer will auto-detect the presence of Windows boot manager and present applicable options for Installation type.

  • Under Installation Type, select "Something else" and continue.

  • Next screen will show the current partitions available on the HDD. Select the un-allocated space and create partitions as described in next steps.

  • UEFI partition : 250MB

  • Boot partition : 250MB

  • Root partition : 48GB

  • Swap: remaining space

  • Important step: To install boot loader: Select the UEFI partition which was created in above steps. Do not select the existing UEFI partition which is used by Windows 10.

  • Continue to begin the installation.

Once installation is over, reboot the system. You will see GRUB loaded with the options to boot Ubuntu or Windows 10.

At this step, you can verify that both the OSes are working fine.

Now, reboot the system again and enter into the UEFI settings by pressing appropriate button during boot-up (in my case it is F2).

You will observe that there are multiple options in the UEFI boot menu.

  • Ubuntu
  • Windows 10
  • And one or two more entries

Now make Windows 10 as the first option for booting.

Save the settings and exit UEFI setup.

You'll observe that now Windows 10 is booting directly without giving any selection option for Ubuntu. Since, we have not used the Windows 10 UEFI partition, so windows boot manager is intact.

Now, in order to boot Ubuntu, press F12 (in other laptop models it may be different) during system startup to see the UEFI boot menu. Select Ubuntu to boot.

  • Note: ST Microelectronics 3-axis digital accelerometer was not detected by Ubuntu 14.04, so automatic changeover to portrait mode will not work in table mode.
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