How to loop a screen page in NES/Famicom vertically?

Question

C++ / C#

I am writing a game for NES/Famicom/Dendy,
using MMC3 mapper and additional video memory.
There is a map that is drawn on the and pages $2000, $2400and
a panel with information on the page. $2800

You need to loop the screen pages $2000and $2400vertically
so that when the camera pans vertically, the lower pages are not displayed.
A similar method is used in the game Crystalis

After a long time poking around in debugging, I just figured out how to fix a piece of the screen to display it as a panel.
But with the looping of the tilemap, I did not figure it out.

this is what the current result looks like...
If there is any information about this, I will be glad.
Since attempts to google lead only to descriptions of the simplest parallax.