SANBoot ISO Image - Not Available For Install

[Azuma Hazuki]

So, this is something I've seen a few threads about, but never found a satisfactory solution to.

Suppose I SANBoot, let's say, debian-8.3.0-amd64-netboot.iso. It starts well enough, but after the GRUB prompt the installer complains that there's no "Common CD-ROM Drive," i.e., it can't see the ISO any longer. This happens in its own way when SANBoot'ing a Windows 7 iso too.

Is there any way to somehow load the entire iso into RAM, or otherwise make the machine aware of its contents?

I have successfully gotten Debian going by untar'ing its netinstall tarball on the remote host and using iPXE's kernel and initrd directives to point to the linux and initrd.gz, but an ISO would be much more convenient.