DIY multiboot?

[IoSer]

I've had an Intel 1 TB SSD sitting here in the box for a few weeks because I haven't decided what to do with it.  I'd like to have at least 2 operating systems on it.

I get that a boot menu (like GRUB) isn't going to work because there's no video until the driver loads.  But what if you load a very minimal Linux partition with the video driver, then write a small boot menu (in C) that boots your choice of OS.  It could be on the eMMC even, the SSD doesn't need to be bootable directly.

Except I don't know what to do in C to boot another partition because I've never done it.  Would I just system() a kernel with a full path and command line options?  Probably not, and what if the kernel isn't Linux, like an OpenBSD one?  system() probably isn't going to like that.

Look at petit boot, search for odroid N1