map size

0) Some garbage data is loaded into the 0x02001000-0x0200FFFF range dependending on the map (or something like that, lower bound doesn't matter) (map data is 0x02010000 - 0x0201FFFF, so going oob off the top of the screen starts reading crap in the range above)

Method 1
1) Go to desired map
2) Open up memory viewer in VBA and go to 0x0200FFFF
3) scroll up until you see non-zero entries in the memory
4) compare with map from area you're going oob in


Method 2
1) 0x020301B4 (or B8 I forget) holds the address to the tile being read, go there in the memory viewer
2) walk oob until you stop moving, check what value is in that address
3) go to that address in the memory viewer
4) load into the desired map and compare the data between the two