diff --git a/src/main/java/com/github/steveice10/mc/protocol/data/MagicValues.java b/src/main/java/com/github/steveice10/mc/protocol/data/MagicValues.java
index 4ed1b776..a65087fb 100644
--- a/src/main/java/com/github/steveice10/mc/protocol/data/MagicValues.java
+++ b/src/main/java/com/github/steveice10/mc/protocol/data/MagicValues.java
@@ -262,7 +262,7 @@ public class MagicValues {
         register(CombatState.END_COMBAT, 1);
         register(CombatState.ENTITY_DEAD, 2);
 
-        register(GameMode.UNKNOWN, -1);
+        register(GameMode.UNKNOWN, 255); // https://bugs.mojang.com/browse/MC-189885 - should be -1
         register(GameMode.SURVIVAL, 0);
         register(GameMode.CREATIVE, 1);
         register(GameMode.ADVENTURE, 2);
diff --git a/src/main/java/com/github/steveice10/mc/protocol/data/game/entity/player/GameMode.java b/src/main/java/com/github/steveice10/mc/protocol/data/game/entity/player/GameMode.java
index 73fa9235..2766052c 100644
--- a/src/main/java/com/github/steveice10/mc/protocol/data/game/entity/player/GameMode.java
+++ b/src/main/java/com/github/steveice10/mc/protocol/data/game/entity/player/GameMode.java
@@ -1,10 +1,6 @@
 package com.github.steveice10.mc.protocol.data.game.entity.player;
 
-import com.github.steveice10.mc.protocol.data.MagicValues;
 import com.github.steveice10.mc.protocol.data.game.world.notify.ClientNotificationValue;
-import com.github.steveice10.packetlib.io.NetOutput;
-
-import java.io.IOException;
 
 public enum GameMode implements ClientNotificationValue {
     SURVIVAL,
diff --git a/src/main/java/com/github/steveice10/mc/protocol/packet/ingame/server/world/ServerNotifyClientPacket.java b/src/main/java/com/github/steveice10/mc/protocol/packet/ingame/server/world/ServerNotifyClientPacket.java
index c49b92d1..90a2582e 100644
--- a/src/main/java/com/github/steveice10/mc/protocol/packet/ingame/server/world/ServerNotifyClientPacket.java
+++ b/src/main/java/com/github/steveice10/mc/protocol/packet/ingame/server/world/ServerNotifyClientPacket.java
@@ -34,7 +34,7 @@ public class ServerNotifyClientPacket implements Packet {
         this.notification = MagicValues.key(ClientNotification.class, in.readUnsignedByte());
         float value = in.readFloat();
         if(this.notification == ClientNotification.CHANGE_GAMEMODE) {
-            this.value = MagicValues.key(GameMode.class, (int) value);
+            this.value = MagicValues.key(GameMode.class, ((int) value == -1) ? 255 : (int) value); // https://bugs.mojang.com/browse/MC-189885 - since we read as a float this bug doesn't apply here
         } else if(this.notification == ClientNotification.DEMO_MESSAGE) {
             this.value = MagicValues.key(DemoMessageValue.class, (int) value);
         } else if(this.notification == ClientNotification.ENTER_CREDITS) {
@@ -52,7 +52,9 @@ public class ServerNotifyClientPacket implements Packet {
     public void write(NetOutput out) throws IOException {
         out.writeByte(MagicValues.value(Integer.class, this.notification));
         float value = 0;
-        if(this.value instanceof Enum<?>) {
+        if (this.value instanceof GameMode && this.value == GameMode.UNKNOWN) {
+            value = -1;
+        } else if(this.value instanceof Enum<?>) {
             value = MagicValues.value(Integer.class, (Enum<?>) this.value);
         } else if(this.value instanceof RainStrengthValue) {
             value = ((RainStrengthValue) this.value).getStrength();