I'm trying to boot an ISO containing a Linux live system from an existing NTFS partition on a PC. The PC has UEFI, and the hard disk is partitioned with GPT, so GRUB4DOS is not an option. Can this be done at all?

I know that the question has been asked before: Grub - boot debian iso file from ntfs partition and install it, but there is no approved answers there - that's why I'm asking again. Also I would like to use my own kernel instead of some fixed and precompiled one.

From the other answers it seems like I would need to include some sort of customized kernel file (I assume place it to EFI partition), which is then capable of loading the rest of the ISO(?) from the NTFS itself.

This can be done on FAT partition already, by simply doing a GRUB entry

menuentry "Boot LINUX FROM ISO FILE" {
  set iso_path=/path_to/image_on_FAT_filesystem.iso
  loopback loop (hdX,msdosY)$iso_path
  linux (loop)/path_to/vmlinuz nomagic base_only norootcopy from=$iso_path
}