diff --git a/src/main/java/org/allaymc/protocol/extension/codec/v630/serializer/PlayerAuthInputSerializer_v630_NetEase.java b/src/main/java/org/allaymc/protocol/extension/codec/v630/serializer/PlayerAuthInputSerializer_v630_NetEase.java
index c27b0de..af29ffd 100644
--- a/src/main/java/org/allaymc/protocol/extension/codec/v630/serializer/PlayerAuthInputSerializer_v630_NetEase.java
+++ b/src/main/java/org/allaymc/protocol/extension/codec/v630/serializer/PlayerAuthInputSerializer_v630_NetEase.java
@@ -26,7 +26,11 @@ public void serialize(ByteBuf buffer, BedrockCodecHelper helper, PlayerAuthInput
         buffer.writeFloatLE(packet.getMotion().getX());
         buffer.writeFloatLE(packet.getMotion().getY());
         buffer.writeFloatLE(rotation.getZ());
-        helper.writeLargeVarIntFlags(buffer, packet.getInputData(), PlayerAuthInputData.class);
+        long flagValue = 0;
+        for (PlayerAuthInputData data : packet.getInputData()) {
+            flagValue |= (1L << data.ordinal());
+        }
+        VarInts.writeUnsignedLong(buffer, flagValue);
         VarInts.writeUnsignedInt(buffer, packet.getInputMode().ordinal());
         VarInts.writeUnsignedInt(buffer, packet.getPlayMode().ordinal());
         writeInteractionModel(buffer, helper, packet);
@@ -60,7 +64,12 @@ public void deserialize(ByteBuf buffer, BedrockCodecHelper helper, PlayerAuthInp
         packet.setMotion(Vector2f.from(buffer.readFloatLE(), buffer.readFloatLE()));
         float z = buffer.readFloatLE();
         packet.setRotation(Vector3f.from(x, y, z));
-        helper.readLargeVarIntFlags(buffer, packet.getInputData(), PlayerAuthInputData.class);
+        long flagValue = VarInts.readUnsignedLong(buffer);
+        for (PlayerAuthInputData flag : PlayerAuthInputData.values()) {
+            if ((flagValue & (1L << flag.ordinal())) != 0) {
+                packet.getInputData().add(flag);
+            }
+        }
         packet.setInputMode(INPUT_MODES[VarInts.readUnsignedInt(buffer)]);
         packet.setPlayMode(CLIENT_PLAY_MODES[VarInts.readUnsignedInt(buffer)]);
         readInteractionModel(buffer, helper, packet);
diff --git a/src/main/java/org/allaymc/protocol/extension/codec/v686/BedrockCodecHelper_v686_NetEase.java b/src/main/java/org/allaymc/protocol/extension/codec/v686/BedrockCodecHelper_v686_NetEase.java
new file mode 100644
index 0000000..0d53dc1
--- /dev/null
+++ b/src/main/java/org/allaymc/protocol/extension/codec/v686/BedrockCodecHelper_v686_NetEase.java
@@ -0,0 +1,67 @@
+package org.allaymc.protocol.extension.codec.v686;
+
+import io.netty.buffer.ByteBuf;
+import org.cloudburstmc.protocol.bedrock.codec.EntityDataTypeMap;
+import org.cloudburstmc.protocol.bedrock.codec.v575.BedrockCodecHelper_v575;
+import org.cloudburstmc.protocol.bedrock.data.Ability;
+import org.cloudburstmc.protocol.bedrock.data.PlayerAuthInputData;
+import org.cloudburstmc.protocol.bedrock.data.inventory.ContainerSlotType;
+import org.cloudburstmc.protocol.bedrock.data.inventory.itemstack.request.TextProcessingEventOrigin;
+import org.cloudburstmc.protocol.bedrock.data.inventory.itemstack.request.action.ItemStackRequestActionType;
+import org.cloudburstmc.protocol.common.util.TypeMap;
+import org.cloudburstmc.protocol.common.util.VarInts;
+
+import java.math.BigInteger;
+import java.util.Set;
+
+/**
+ * NetEase variant of the v686 codec helper.
+ * Implements readLargeVarIntFlags/writeLargeVarIntFlags with NetEase flag offset adaptation (neteaseFlags1212).
+ *
+ * @author LT_Name
+ */
+public class BedrockCodecHelper_v686_NetEase extends BedrockCodecHelper_v575 {
+
+    // NetEase inserts an extra flag at this position (after RECEIVED_SERVER_DATA)
+    private static final int PLAYER_AUTH_INPUT_DATA_NETEASE = PlayerAuthInputData.RECEIVED_SERVER_DATA.ordinal() + 1;
+
+    public BedrockCodecHelper_v686_NetEase(EntityDataTypeMap entityData, TypeMap<Class<?>> gameRulesTypes, TypeMap<ItemStackRequestActionType> stackRequestActionTypes, TypeMap<ContainerSlotType> containerSlotTypes, TypeMap<Ability> abilities, TypeMap<TextProcessingEventOrigin> textProcessingEventOrigins) {
+        super(entityData, gameRulesTypes, stackRequestActionTypes, containerSlotTypes, abilities, textProcessingEventOrigins);
+    }
+
+    @Override
+    public <T extends Enum<?>> void readLargeVarIntFlags(ByteBuf buffer, Set<T> flags, Class<T> clazz) {
+        var needNetEaseAdaptation = clazz == PlayerAuthInputData.class;
+        BigInteger flagsInt = VarInts.readUnsignedBigVarInt(buffer, clazz.getEnumConstants().length);
+        for (T flag : clazz.getEnumConstants()) {
+            var ordinal = flag.ordinal();
+            if (needNetEaseAdaptation) {
+                if (ordinal == PLAYER_AUTH_INPUT_DATA_NETEASE) {
+                    // Ignore PlayerAuthInputData.NETEASE
+                    continue;
+                }
+
+                if (ordinal > PLAYER_AUTH_INPUT_DATA_NETEASE) {
+                    ordinal -= 1;
+                }
+            }
+            if (flagsInt.testBit(ordinal)) {
+                flags.add(flag);
+            }
+        }
+    }
+
+    @Override
+    public <T extends Enum<?>> void writeLargeVarIntFlags(ByteBuf buffer, Set<T> flags, Class<T> clazz) {
+        var needNetEaseAdaptation = clazz == PlayerAuthInputData.class;
+        BigInteger flagsInt = BigInteger.ZERO;
+        for (T flag : flags) {
+            var ordinal = flag.ordinal();
+            if (needNetEaseAdaptation && ordinal >= PLAYER_AUTH_INPUT_DATA_NETEASE) {
+                ordinal += 1;
+            }
+            flagsInt = flagsInt.setBit(ordinal);
+        }
+        VarInts.writeUnsignedBigVarInt(buffer, flagsInt);
+    }
+}
diff --git a/src/main/java/org/allaymc/protocol/extension/codec/v686/Bedrock_v686_NetEase.java b/src/main/java/org/allaymc/protocol/extension/codec/v686/Bedrock_v686_NetEase.java
index 65b3a1d..685d8b1 100644
--- a/src/main/java/org/allaymc/protocol/extension/codec/v686/Bedrock_v686_NetEase.java
+++ b/src/main/java/org/allaymc/protocol/extension/codec/v686/Bedrock_v686_NetEase.java
@@ -12,7 +12,6 @@
 import org.allaymc.protocol.extension.packet.StoreBuySuccessPacket;
 import org.allaymc.protocol.extension.codec.common.serializer.PlayerEnchantOptionsSerializer_v407_NetEase;
 import org.cloudburstmc.protocol.bedrock.codec.BedrockCodec;
-import org.cloudburstmc.protocol.bedrock.codec.v575.BedrockCodecHelper_v575;
 import org.cloudburstmc.protocol.bedrock.codec.v686.Bedrock_v686;
 import org.cloudburstmc.protocol.bedrock.data.PacketRecipient;
 import org.cloudburstmc.protocol.bedrock.data.inventory.ContainerSlotType;
@@ -36,7 +35,7 @@ public class Bedrock_v686_NetEase extends Bedrock_v686 {
 
     public static final BedrockCodec CODEC = Bedrock_v686.CODEC.toBuilder()
             .raknetProtocolVersion(8)
-            .helper(() -> new BedrockCodecHelper_v575(ENTITY_DATA, GAME_RULE_TYPES, ITEM_STACK_REQUEST_TYPES, CONTAINER_SLOT_TYPES, PLAYER_ABILITIES, TEXT_PROCESSING_ORIGINS))
+            .helper(() -> new BedrockCodecHelper_v686_NetEase(ENTITY_DATA, GAME_RULE_TYPES, ITEM_STACK_REQUEST_TYPES, CONTAINER_SLOT_TYPES, PLAYER_ABILITIES, TEXT_PROCESSING_ORIGINS))
             .updateSerializer(PlayerAuthInputPacket.class, PlayerAuthInputSerializer_v686_NetEase.INSTANCE)
             .updateSerializer(TextPacket.class, TextSerializer_v686_NetEase.INSTANCE)
             .updateSerializer(PlayerEnchantOptionsPacket.class, PlayerEnchantOptionsSerializer_v407_NetEase.INSTANCE)