This is the full Project to overwrite MBR. If you ask its possible overwrite the message of MBR without visual studio (USE HXD), "you can open my project, and overwrite your cutom message using hexadecimal editor like Hiew"
Bulid instructions on my channel. Your own responsability.
12/04/2021 My apologies, i was dumb and i couldn't write properly in english, i guess now it is fixed, and well, after use Hiew, instead use HxD, that's a trash program lol, and also the video itself sucks, i didn't know how to edit... But i think it is well explained.