Homebrew Top/Bottom LCD Framebuffer Select register writes in GSP

[cal64]

I've been trying to get the bottom screen to display the top screen framebuffer.
So far I've set the top LCD's framebuffer adress1/2, format, select, and stride register writes to the bottom LCD.

My problem is that some games, namely SM3DL and the top-down zeldas,
behave as though they're still writing to each screen's fb select reg separately.

I couldnt find any other writes to said registers in GSP's code that could produce this behavior. Anyone know where they could be?

EDIT: My bad, turns out they're writes to fb addr registers. Sorry!