Then you realize it was this guy: https://en.wikipedia.org/wiki/Erik_Demaine
His lectures are absolute gold. He explains everything so clearly, simply, and efficiently.
I started skipping lectures in favor of watching his videos, and it saved me countless of hours -- and I got a perfect mark :)
I miss the days of reading AMD64 manuals and directly interacting with my hardware through assembly, and I want to get back to it.
What would be a good entry-point to OS development nowadays? I have the "FYSOS: The System Core" by Benjamin David Lunt. While I love the series, I wonder what other alternatives there are, perhaps supporting ARM?