Unable to mount iso image from installer's initramfs

[Alexander--]

According to https://git.archlinux.org/archiso.git/tree/docs/README.altbootmethods, archiso supports booting from iso image, located on arbitrary storage. I tried to boot official Arch iso via grub's loopback, and it works as documented.

When I am trying to do same with artix installation iso (artix-i3-rolling-x86_64.iso), the installer fails to mount iso image: mounting overlayfs fails, and when I try to mount installer's image manually, that fails with error message:

mount: unknown filesystem type 'iso9660'

Is loopback iso mount supported by Artix installer?