Multiple OS on SD card

[z4v4l]

Only if I understand correctly (and maybe I'm wrong) that software to make multiboot is not or not yet opensource.

scary. how dared they not to open sauce! sometimes it looks like people need only opensource. not the functionality, utility, usefulness, just opensource for the sake of open source. if I'm wrong, then why are there such exclamation notes like the quoted.
anyway, the guy in question, said the GUI part of that thing won't be opensauce.
and btw, keep in mind, that making more than one, non-FAT partition on an SD card, you break the compliance with the specification, the card may or may not work properly after such modificattions. also, even operating properly, at the first glance, it may degrade its wear protection mechanisms, since the internal controller assumes and relies on the specified layout for the card (single FAT partition, whose internal structures are instrumental for it in its decisions).