diff --git a/core/src/io/anuke/mindustry/io/TypeIO.java b/core/src/io/anuke/mindustry/io/TypeIO.java
index a8829cb90a..94b3f0825f 100644
--- a/core/src/io/anuke/mindustry/io/TypeIO.java
+++ b/core/src/io/anuke/mindustry/io/TypeIO.java
@@ -335,15 +335,14 @@ public class TypeIO{
             buffer.putShort((short) bytes.length);
             buffer.put(bytes);
         }else{
-            buffer.put((byte) -1);
+            buffer.putShort((short) -1);
         }
     }
 
     @ReadClass(String.class)
     public static String readString(ByteBuffer buffer){
-        byte length = buffer.get();
-        if(length != -1){
-            short slength = buffer.getShort();
+        short slength = buffer.getShort();
+        if(slength != -1){
             byte[] bytes = new byte[slength];
             buffer.get(bytes);
             return new String(bytes, StandardCharsets.UTF_8);
@@ -372,14 +371,13 @@ public class TypeIO{
             buffer.writeShort((short) bytes.length);
             buffer.write(bytes);
         }else{
-            buffer.writeByte((byte) -1);
+            buffer.writeShort((short) -1);
         }
     }
 
     public static String readStringData(DataInput buffer) throws IOException{
-        byte length = buffer.readByte();
-        if(length != -1){
-            short slength = buffer.readShort();
+        short slength = buffer.readShort();
+        if(slength != -1){
             byte[] bytes = new byte[slength];
             buffer.readFully(bytes);
             return new String(bytes, StandardCharsets.UTF_8);
diff --git a/tests/src/test/java/IOTests.java b/tests/src/test/java/IOTests.java
new file mode 100644
index 0000000000..5357bb515e
--- /dev/null
+++ b/tests/src/test/java/IOTests.java
@@ -0,0 +1,34 @@
+import io.anuke.mindustry.io.TypeIO;
+import org.junit.jupiter.api.Test;
+
+import java.nio.ByteBuffer;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class IOTests{
+
+    @Test
+    void writeEnglish(){
+        ByteBuffer buffer = ByteBuffer.allocate(500);
+        TypeIO.writeString(buffer, "asd asd asd asd asdagagasasjakbgeah;jwrej 23424234");
+        buffer.position(0);
+        assertEquals(TypeIO.readString(buffer), "asd asd asd asd asdagagasasjakbgeah;jwrej 23424234");
+    }
+
+    @Test
+    void writeChinese(){
+        ByteBuffer buffer = ByteBuffer.allocate(500);
+        TypeIO.writeString(buffer, "这个服务器可以用自己的语言说话");
+        buffer.position(0);
+        assertEquals(TypeIO.readString(buffer), "这个服务器可以用自己的语言说话");
+    }
+
+    @Test
+    void writeNull(){
+        ByteBuffer buffer = ByteBuffer.allocate(500);
+        TypeIO.writeString(buffer, null);
+        buffer.position(0);
+        assertEquals(TypeIO.readString(buffer), null);
+    }
+
+}