Finally, I made a BSD-licensed version of all the FAT12/16/32 versions of this boot sector, cleaned up code comments and threw in a utility to make floppy images (ready for VMs or for dd'ing onto physical floppies) with this (or another) boot sector and any files of choice.The "BootProg" Boot Sector
What is BootProg?
BootProg is a collection of 512-byte boot sectors (for the x86 PC) capable of
loading and executing a program from a FAT12-formatted floppy or a FAT16/32-
formatted hard disk (bootable USB sticks and CDs can also be made with
BootProg).
BootProg understands programs in the MS-DOS .COM or .EXE format. This makes
it possible to use existing 16-bit compilers such as Borland/Turbo C/C++,
Sybase/Open Watcom C/C++ and Smaller C and a variety of assemblers such as
NASM, FASM, TASM and MASM among the others.
BootProg doesn't require that the program occupy a contiguous span of sectors
or FAT clusters or reside at a specific fixed location on the disk. BootProg
faithfully parses the root directory and the chain of FAT clusters in order to
locate the program contents. The only requirement is that the program be named
"STARTUP.BIN" (without quotes). This makes updating the program easy. You just
need to update the file and you can reboot and execute it immediately.
What can BootProg be used for?
You can make a boot loader for your OS. The program that BootProg loads can be
your 2nd stage boot loader. Or, if your OS is relatively small, STARTUP.BIN
could contain the entire OS.
You can write low-level utilities to work with your PC's hardware and load them
with BootProg without having to jump through the hoops with your Windows, Linux
or even DOS.
You can make cool graphics demos or games that run on bare hardware.
...
https://github.com/alexfru/BootProg
Enjoy!