I've got a hobby OS that runs on real hardware (sometimes, on some hardware). Mostly it's just patience and debugging effort to get things going. qemu defaults to doing some things quickly instead of accurately, so it's easy to do things wrong as an OS and if you don't test regularly, you can end up with a lot of breakage.

I don't have a boot manager, my OS is multiboot compatible, so I can boot with qemu's multiboot support or PXElinux, or grub or whatever. IMHO, with the multiboot standard, there's no need to write a boot loader if you want to build an OS, and no need to write an OS if you want to build a boot loader.

Looks like this OS has a good selection of storage drivers, so should be good to go there.