Earlier quoted context omitted.
Basically what userbinator said. I had to deal with them before, so if you can, stay away from cheap Chinese boards or hackable routers. When you're just learning, it's not worth it, the dollars you save will be more than made up in working around subtle bugs and trying to figure out what the poorly-worded, incomplete documentation is trying to convey. I also warmly suggest not to bother with anything that says Ather…
Do you, by any chance, know of a resource that documents the process of actually getting your toy OS (which I assume was cross-compiled) to run on another board such as the BBB or the RPi?
I don't know of any documents, but the way you'd generally want to do it is wrap hardware- and board-specific parts of your code in a hardware-agnostic interface which is what you use to write higher-level code in the system. That way, getting the OS to run on another CPU or board is all about writing the relevant callbacks. You can get the general idea from Linux's mach-* and plat-* files. This isn't really OS-specific; I'm pointing at Linux because it will probably be easiest to get documentation about it, though my personal preference is elsewhere.