diff --git a/src/pocketmine/level/format/io/BaseLevelProvider.php b/src/pocketmine/level/format/io/BaseLevelProvider.php
index 1a4f2e90e..664dd2586 100644
--- a/src/pocketmine/level/format/io/BaseLevelProvider.php
+++ b/src/pocketmine/level/format/io/BaseLevelProvider.php
@@ -61,6 +61,8 @@ abstract class BaseLevelProvider implements LevelProvider{
 	protected function fixLevelData() : void{
 		if(!$this->levelData->hasTag("generatorName", StringTag::class)){
 			$this->levelData->setString("generatorName", "default", true);
+		}elseif(($generatorName = self::hackyFixForGeneratorClasspathInLevelDat($this->levelData->getString("generatorName"))) !== null){
+			$this->levelData->setString("generatorName", $generatorName);
 		}
 
 		if(!$this->levelData->hasTag("generatorOptions", StringTag::class)){
@@ -68,6 +70,35 @@ abstract class BaseLevelProvider implements LevelProvider{
 		}
 	}
 
+	/**
+	 * Hack to fix worlds broken previously by older versions of PocketMine-MP which incorrectly saved classpaths of
+	 * generators into level.dat on imported (not generated) worlds.
+	 *
+	 * This should only have affected leveldb worlds as far as I know, because PC format worlds include the
+	 * generatorName tag by default. However, MCPE leveldb ones didn't, and so they would get filled in with something
+	 * broken.
+	 *
+	 * This bug took a long time to get found because previously the generator manager would just return the default
+	 * generator silently on failure to identify the correct generator, which caused lots of unexpected bugs.
+	 *
+	 * Only classnames which were written into the level.dat from "fixing" the level data are included here. These are
+	 * hardcoded to avoid problems fixing broken worlds in the future if these classes get moved, renamed or removed.
+	 *
+	 * @param string $className Classname saved in level.dat
+	 *
+	 * @return null|string Name of the correct generator to replace the broken value
+	 */
+	protected static function hackyFixForGeneratorClasspathInLevelDat(string $className) : ?string{
+		switch($className){
+			case 'pocketmine\level\generator\normal\Normal':
+				return "normal";
+			case 'pocketmine\level\generator\Flat':
+				return "flat";
+		}
+
+		return null;
+	}
+
 	public function getPath() : string{
 		return $this->path;
 	}
diff --git a/src/pocketmine/level/format/io/leveldb/LevelDB.php b/src/pocketmine/level/format/io/leveldb/LevelDB.php
index 1cd8b57ac..a71deb1dd 100644
--- a/src/pocketmine/level/format/io/leveldb/LevelDB.php
+++ b/src/pocketmine/level/format/io/leveldb/LevelDB.php
@@ -142,6 +142,8 @@ class LevelDB extends BaseLevelProvider{
 			}else{
 				$this->levelData->setString("generatorName", "default");
 			}
+		}elseif(($generatorName = self::hackyFixForGeneratorClasspathInLevelDat($this->levelData->getString("generatorName"))) !== null){
+			$this->levelData->setString("generatorName", $generatorName);
 		}
 
 		if(!$this->levelData->hasTag("generatorOptions", StringTag::class)){