diff --git a/index.js b/index.js
index 296f4d7..5f67fdb 100644
--- a/index.js
+++ b/index.js
@@ -8,6 +8,7 @@ var EventEmitter = require('events').EventEmitter
   , protocol = require('./lib/protocol')
   , Client = require('./lib/client')
   , Server = require('./lib/server')
+  , debug = protocol.debug
 
 module.exports = {
   createClient: createClient,
@@ -261,12 +262,12 @@ function createClient(options) {
         return
       }
 
-      var hash = crypto.createHash('sha1');
-      hash.update(packet.serverId);
-
       if (haveCredentials) {
         joinServerRequest(onJoinServerResponse);
       } else {
+        if (packet.serverId != '-') {
+          debug('This server appears to be an online server and you are providing no password, the authentication will probably fail');
+        }
         sendEncryptionKeyResponse();
       }
 
@@ -280,6 +281,8 @@ function createClient(options) {
       }
 
       function joinServerRequest(cb) {
+        var hash = crypto.createHash('sha1');
+        hash.update(packet.serverId);
         hash.update(sharedSecret);
         hash.update(packet.publicKey);
 
@@ -363,7 +366,7 @@ function mcHexDigest(hash) {
       newByte = ~value & 0xff;
       if (carry) {
         carry = newByte === 0xff;
-        buffer.writeUInt8(newByte + 1, i);
+        buffer.writeUInt8((newByte + 1) & 0xff, i);
       } else {
         buffer.writeUInt8(newByte, i);
       }
diff --git a/lib/protocol.js b/lib/protocol.js
index 21be784..0958be1 100644
--- a/lib/protocol.js
+++ b/lib/protocol.js
@@ -776,16 +776,22 @@ function readEntityMetadata(buffer, offset) {
     key = item & 0x1f;
     type = item >> 5;
     typeName = entityMetadataTypes[type];
+    debug("Reading entity metadata type " + type + " (" + ( typeName || "unknown" ) + ")");
+    if (!typeName) {
+      return {
+        error: new Error("unrecognized entity metadata type " + type)
+      }
+    }
     dataType = types[typeName];
     if (!dataType) {
       return {
-        error: new Error("unrecognized entity metadata type " + type)
+        error: new Error("unrecognized entity metadata type name " + typeName)
       }
     }
     reader = dataType[0];
     if (!reader) {
       return {
-        error: new Error("missing reader for entity metadata type " + type)
+        error: new Error("missing reader for entity metadata type name " + typeName)
       }
     }
     results = reader(buffer, cursor);
@@ -1088,6 +1094,7 @@ function readSlot(buffer, offset) {
   var nbtDataSize = buffer.readInt16BE(cursor + 3);
   if (nbtDataSize === -1) nbtDataSize = 0;
   var nbtDataEnd = cursorEnd + nbtDataSize;
+  if (nbtDataEnd > buffer.length) return null;
   var nbtData = buffer.slice(cursorEnd, nbtDataEnd);
 
   return {