diff --git a/paper-server/src/main/java/org/bukkit/craftbukkit/CraftWorld.java b/paper-server/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
index 0aac7caefd..b409580b64 100644
--- a/paper-server/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
+++ b/paper-server/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
@@ -734,7 +734,7 @@ public class CraftWorld extends CraftRegionAccessor implements World {
 
     @Override
     public void setBiome(int x, int z, Biome bio) {
-        for (int y = 0; y < getMaxHeight(); y++) {
+        for (int y = getMinHeight(); y < getMaxHeight(); y++) {
             setBiome(x, y, z, bio);
         }
     }
@@ -746,7 +746,7 @@ public class CraftWorld extends CraftRegionAccessor implements World {
             net.minecraft.world.level.chunk.Chunk chunk = this.world.getChunkAt(pos);
 
             if (chunk != null) {
-                chunk.setBiome(x, y, z, bb);
+                chunk.setBiome(x >> 2, y >> 2, z >> 2, bb);
 
                 chunk.setUnsaved(true); // SPIGOT-2890
             }
diff --git a/paper-server/src/main/java/org/bukkit/craftbukkit/generator/CustomChunkGenerator.java b/paper-server/src/main/java/org/bukkit/craftbukkit/generator/CustomChunkGenerator.java
index 6a5d231065..d65f33a310 100644
--- a/paper-server/src/main/java/org/bukkit/craftbukkit/generator/CustomChunkGenerator.java
+++ b/paper-server/src/main/java/org/bukkit/craftbukkit/generator/CustomChunkGenerator.java
@@ -66,7 +66,7 @@ public class CustomChunkGenerator extends InternalChunkGenerator {
 
         @Override
         public void setBiome(int x, int z, Biome bio) {
-            for (int y = 0; y < world.getWorld().getMaxHeight(); y += 4) {
+            for (int y = world.getWorld().getMinHeight(); y < world.getWorld().getMaxHeight(); y += 4) {
                 setBiome(x, y, z, bio);
             }
         }