I have been installing Ubuntu as many ways as I can. I only had one time when the Windows 7 system was corrupted and a Repair Install took care of that. Error was the bootmgr had to be fixed.
I have managed to load Ubuntu in an EFI situation by adding an EFI partition at the front of the drive. Doing it that way allows me to boot into Windows (Windows Boot Manager) or the drive with Ubuntu if I do so using the F8 key during boot to select a boot device.
I have also managed to dual boot if I installed Ubuntu non-EFI, as you did, and used EasyBCD to set up that boot.