I have a Dell Inspirion laptop stock with Windows 8.1, I have added Ubuntu 14.04. Ubuntu install went perfect, rebooted came to the regualar, grub2 menu, (I say regular because it's the same one I've looked at on my old pc for a couple of years) I choose Ubuntu, it loaded a little more, then another screen popped up with the OS choices, although this looks like a Windows based screen, again I choose Ubuntu, and the desktop loaded, and everything ran perfect. Then rebooting into Windows, again I got the old Familiar grub2 menu, and then what looks like a Windows verseion of the OS choice menu, and again Windows loaded and ran perfect.
So there really isn't a problem with having both screens come up, it's just a little annoying to have to make that choice twice. Now I guess I better mention that I installed Ubuntu on a usb hard drive, it did install using the uefi method, as far as I know, because first it works, I seem to remember that it mentioned uefi while installing, although that was a month ago, so I may be remembering wrong. When I boot up I click the F12 button and pull up the boot order menu, and choose the uefi usb device, and Ubuntu loads, or I press F12 and choose hard drive, and Windows loads.
Putting this on usb was actually more of an experiment than anything, just to see if I could make it work. I don't really want to install to my hard drive at this point, even though installing Linux will not void the warranty, if they can say the problem is caused because of the Linux instillation and get out of repairing it, they will. That's what the manufacturer told me, when I called to ask. He was very honest about it, and said that they will get out of fixing it anyway they can, and that's just giving them something to use. I'm using usb 3.0 stuff, so it's just as fast as if it was installed to the hard drive.
So I have two problems, 1. the two OS choice (grub) menu's, and probably nothing I can do about this as long as I'm usb booting 2. having to press F12 every time I restart the machine, even if the usb drive is unhooked and I'm booting into windows, If I don't F12 then choose hard drive, the boot-up just hangs, on a blank screen, it doesn't know where to find the hard drive apparently.
If anyone has any wisdom, or even criticism, I would be glad to hear it, that's the best way to learn.
Thanks for the advice Robby