There is no support in the installer, the manual approach is needed (from J65nko's link):
http://lists.dragonflybsd.org/piperm...ly/270759.html
You've had no luck perhaps because you have 'unusual' hardware. Even if you somehow get a base system manually installed with DragonFly or NetBSD booting via UEFI, you don't yet know if all the hardware is supported until you can try to boot the kernel.
FreeBSD actually doesn't have a driver for your eMMC so that's simply a non starter. The same may be the case for DragonFly and NetBSD. A Linux dmesg might aid you in finding out more info about the hardware..