I want to dual boot ubuntu 15.10 with already installed windows 10 (upgraded from 8). From what I've been researching, in order for ubtuntu to be dualbooted with windows 10 on a uefi machine, the ubuntu installation media (in this case a usb) must also be booted from uefi (as opposed to changing the boot setting to Legacy and booting from usb that way), so that the correct grub-efi, instead of grub-pc, is installed.
I have a Dell Inspiron 7000 series with core i7 processor its 64bit and also boots windows with uefi. This dell does not seem to support booting a usb from uefi as no matter what I try, "Boot from usb" will NOT appear under "UEFI boot options." The only way for me to boot from the usb is to boot in legacy mode and then select boot from usb. The problem is, when I try to install ubuntu this way, after rebooting, my system boots directly to windows 10 and the grub option does not even appear, let alone the actual bootloader screen to select which OS I want to boot. I assume my problem is that I can not install ubuntu correctly since I have to boot the usb in legacy mode when trying to install.
Also, the filesystem on the usb appears as FAT32 which should be recognizable to windows to support usb uefi booting
Does anyone know of a way I can "Boot from USB" with "UEFI boot option"?
I was following the steps on https://help.ubuntu.com/community/UEFI but under General Principles, number 5, I can not do this with my system. Can anyone help me with a workaround or anything?