You're thinking too hard about this.
Asrock logo stays persistent there. Anyone using LOGOfail are not using it on cyraxx. They are selling it for a shitload of money. And people buying are not using it on Cyraxx, because it would be expensive as fuck.
Also, after each bios flash attempt, Cyraxx turns his computer back on. In a flash, your pc will reboot.
He is being tricked to cut power dur8ng the update, causing the problem,
As for the rat, its not hard to think that someone was feeding him ps scripts to copy/paste to completely shut down wd. Which would let them install something, normally easily detected, with hvnc and all the other fun stuff.
As for persistence? I bet he went to the windows site, downloaded their tool and went from there. The tool will not delete all data. Microsoft needs that to track you.
Or constant social engineering after each reinstall, which would be sweaty work.