im not sure why i didnt think that a bootload can just be flashed as normal - doiiiii (its been about 4 months since ive flashed anything on my device though, in my defense, so im a bit rusty)
i also had an extremely difficult time trying to find the updated bootloader and ended up using the link from @TheAtheistOtaku
even though it seemed kinda sketchy to me
id expect all phones, especially the N5 to have an XDA downloads section/page with explicity labeled updates for all aspects of the phone. i think ive seen similar xda pages for other phones...
anyways i seem to be good to go now! thanks again!