I have problem with dual boot on Windows 10 and Ubuntu 16.04. The hard disk, I am trying to use, was configured on another Lenovo G50 series, with Windows 10 as first OS. At that time, I managed to dual boot both OS without a problem. Recently, the laptop was damged, therefore, I decided to try to use the Hard disk in another Laptop - Lenovo -thinkpad (Enhanced Experience 2.0) with boot mode: UEFI. The laptop started well direct to Windows 10, without Grub loader option for selection.
I did the following steps to install Ubuntu 16.04.
Step 1: Accessed BIOS setup (ThinkPad Setup) by pressing Fn + F1 Key.
For this laptop there is STARTUP tab: with the following options.
A. UEFI/Legacy Boot [Both- system will boot by following UEFI/Legacy Boot Priority setting, UEFI only and Legacy Only. I selected Legacy only so that I can boot from DVD and install Ubuntu, because without it boot on Windows 10.
B.UEFI/Legacy Boot priory.
During partition, for the last option it asked to create a partition for Reverse BIOS boot. I did that, however, After rebooting and returning to Both option in A, boot direct to MS Windows 10, without selection option.