diff --git a/ClassicalSharp/Network/NetworkProcessor.CPE.cs b/ClassicalSharp/Network/NetworkProcessor.CPE.cs
index da83deb18..49fd44842 100644
--- a/ClassicalSharp/Network/NetworkProcessor.CPE.cs
+++ b/ClassicalSharp/Network/NetworkProcessor.CPE.cs
@@ -60,6 +60,7 @@ namespace ClassicalSharp.Net {
 		int cpeServerExtensionsCount;
 		bool sendHeldBlock, useMessageTypes;
 		int envMapAppearanceVer = 2, blockDefinitionsExtVer = 2;
+		bool needD3Fix;
 		static string[] clientExtensions = {
 			"ClickDistance", "CustomBlocks", "HeldBlock", "EmoteFix", "TextHotKey", "ExtPlayerList",
 			"EnvColors", "SelectionCuboid", "BlockPermissions", "ChangeModel", "EnvMapAppearance",
@@ -70,6 +71,8 @@ namespace ClassicalSharp.Net {
 		void HandleCpeExtInfo() {
 			string appName = reader.ReadAsciiString();
 			game.Chat.Add( "Server software: " + appName );
+			if( Utils.CaselessStarts( appName, "D3 server" ) )
+				needD3Fix = true;
 			
 			// Workaround for MCGalaxy that send ExtEntry sync but ExtInfoAsync. This means
 			// ExtEntry may sometimes arrive before ExtInfo, and thus we have to use += instead of =
diff --git a/ClassicalSharp/Network/NetworkProcessor.cs b/ClassicalSharp/Network/NetworkProcessor.cs
index 69e76a3e0..8ffff63aa 100644
--- a/ClassicalSharp/Network/NetworkProcessor.cs
+++ b/ClassicalSharp/Network/NetworkProcessor.cs
@@ -44,6 +44,7 @@ namespace ClassicalSharp.Net {
 			gzippedMap = new FixedBufferStream( reader.buffer );
 			envMapAppearanceVer = 2;
 			blockDefinitionsExtVer = 2;
+			needD3Fix = false;
 			
 			Disconnected = false;
 			receivedFirstPosition = false;
@@ -82,7 +83,8 @@ namespace ClassicalSharp.Net {
 			while( (reader.size - reader.index) > 0 ) {
 				byte opcode = reader.buffer[reader.index];
 				// Workaround for older D3 servers which wrote one byte too many for HackControl packets.
-				if( opcode == 0xFF && lastOpcode == PacketId.CpeHackControl ) {
+				if( needD3Fix && lastOpcode == PacketId.CpeHackControl && (opcode == 0x00 || opcode == 0xFF) ) {
+					Utils.LogDebug( "Skipping invalid HackControl byte from D3 server." );
 					reader.Skip( 1 );
 					player.physics.jumpVel = 0.42f; // assume default jump height
 					player.physics.serverJumpVel = player.physics.jumpVel;