first of all thanks for your time and sorry for my english and my lack of computer skills. I have a problem with my HP Pavilion g6 Notebook. I made a Bootable USB with a Lubuntu 18.04 ISO using Rufus. However there's no way I can boot it in UEFI mode on Windows 8.1. I disabled secure boot and fast boot and I also tried to force the USB boot but an error occurred saying that "The device have failed to boot". Same thing using a DVD. Anyway when I enabled Legacy Mode everything has worked fine and I made to install the new OS. The only issue was that GRUB didn't showed up and I had to manually boot into it.
Since I've read that two different OS should be both installed in the same bios (Legacy or UEFI) can you help me to resolve the UEFI issue on my notebook?