Now the tiles appear to be scrolling from the bottom and disappearing when they touch the top of the screen.
I don't understand what you're trying to do. If you want to scroll the screen just call the ROM routine at 3582
I put 0 in accumulator and called 5633 and this is what happened.
(the same thing happens when I put 1)
What I'm trying to do is be able to put UDGs and text on the bottom of the screen without the "scroll?" thing ruining it.
Once you've opened the lower screen for printing, make sure you reset the cursor position to the top left. Printing chr$ 22, chr$ 0 and then chr$ 0 will do that. Then you should be able to put another 64 characters in the bottom panel. Don't go beyond that or that part of the screen will scroll up