I have made a LiveCD using this guide plus additional searches on internet, and I have made a functional system using packages from Ubuntu xenial repositories: it can boot, the system can be used, wireless worked on all notebooks I have tested and it can be installed with Ubiquity (I am impressed).
The problem is: I was able to boot only in BIOS mode. On UEFI mode, nothing appears, not even GRUB rescue, so something is completely wrong.
I have tried to copy the boot and EFI directly from the Ubuntu's ISO, which didn't work. The Ubuntu's ISO has some files, particularly casper/vmlinuz.efi, EFI/BOOT/bootx64.efi and EFI/BOOT/grubx64.efi which, no matter what I do, I was not able to create or find. I've found only vmlinuz, which hasn't the .efi extension, and the other two, I have no idea how to create those files.
To boot the computer in BIOS mode, I am using isolinux, which works. I tried with syslinux to boot on UEFI mode too, but had no success, so I am trying to use GRUB, as is done in the Ubuntu's LiveCD.
What are the required steps to make the LiveCD I have made to boot in UEFI mode, as the Ubuntu one does? I believe I would need to create special files. If yes, how do I create them?