Fix broken Overworld

mods/CORE/mcl_init/init.lua

@@ -50,7 +50,7 @@ else
 	mcl_vars.mg_bedrock_is_rough = false
 end
 
-mcl_vars.mg_overworld_max = math.huge
+mcl_vars.mg_overworld_max = 31000
 
 -- The Nether
 mcl_vars.mg_nether_min = -29000

mods/MAPGEN/mcl_biomes/init.lua

@@ -545,7 +545,7 @@ local function register_biomes()
 	minetest.register_biome({
 		name = "underground",
 		y_min = mcl_vars.mg_overworld_min,
-		y_max = mcl_util.y_to_layer(61),
+		y_max = mcl_util.layer_to_y(61),
 		heat_point = 50,
 		humidity_point = 50,
 	})