First of all, moderators please advise if this post is obsolete.
I had spent two full days trying to get the updated bootloader to replace the deprecated Emcore Bootloader, and - in the end - got some amazing help from prof_wolfff, one of the developers.
I'm sure it'll be helpful to anyone having trouble with their installation, and it's two very basic things:
1. No matter how "bricked" your iPod may seem, or rather: no matter how impossible it may seem to get into DFU-Mode, JUST HOLD "SELECT + MENU" long enough. That's it.
2. If you're having trouble using mks5lboot, make sure you have the correct version (Linux/Mac/Windows) for your OS. "Command not found" errors are frustrating and mysterious if you have done everything else correctly.
3. If your iTunes is unable to restore your iPod to its original state, go here:
https://www.freemyipod.org/wiki/Restore_iPod_without_iTunesRockbox ROCKS!