--- ../src_base/common/net/minecraft/src/Packet56MapChunks.java
+++ ../src_work/common/net/minecraft/src/Packet56MapChunks.java
@@ -121,7 +121,13 @@
                 var7 += this.field_73590_a[var6] >> var8 & 1;
             }
 
-            var8 = 2048 * 5 * var7 + 256;
+            int msb = 0; //BugFix: MC does not read the MSB array from the packet properly, causing issues for servers that use blocks > 256
+            for (var8 = 0; var8 < 16; ++var8)
+            {
+                msb += this.field_73588_b[var6] >> var8 & 1;
+            }
+
+            var8 = 2048 * 5 * var7 + (2048 * msb) + 256;
             this.field_73584_f[var6] = new byte[var8];
             System.arraycopy(var3, var5, this.field_73584_f[var6], 0, var8);
             var5 += var8;