Thanks for giving it a look! You're certainly right about UEFI. I figured it would be easier and informative enough in the long run to just write a simple MBR bootloader instead of an EFI-format one.
Either way, it was definitely fun.
Either way, it was definitely fun.
http://www.advancemame.it/doc-makebootfat
and for an example of how much stuff you can actually put inside some 440 bytes, the base reference is mbldr: